The mood among opposition supporters in Istanbul is one of jubilation, mixed with worry, as their apparent narrow win in mayoral elections could be overturned after President Recep Tayyip Erdogan's governing party challenged the results, prompting a recount.

In an unexpected setback to the president, the opposition appeared to have won Sunday's tight race in the city, the country's financial and cultural capital where Erdogan himself rose to power as mayor.

Joy over candidate Ekrem Imamoglu’s razor-thin win has given way to concerns after the ruling Justice and Development Party, or AKP, contested results in all of Istanbul’s 39 districts, alleging fraud and demanding a recount of votes deemed invalid.

Electoral authorities, whose independence opposition parties have questioned in the past, allowed recounts in at least 18 districts.

A senior AKP official on Thursday said the gap in votes had now further narrowed to around 19,000 - from around 25,000 announced on Monday.

The AKP has put up posters around Istanbul featuring pictures of Erdogan and the AKP's candidate, former prime minister Binali Yildirim, and thanking residents for their support - a move that many regard as a premature declaration of victory.  

Yildirim himself had declared victory on Sunday, before acknowledging that Imamoglu had a narrow lead.

Imamoglu himself tweeted on Friday he was leading by 18,742 votes.

His backers denounce what they see as two sets of rules for the ruling party and the opposition, recalling that similar appeals by their secular Republican People's Party were derided and rejected in past elections.

Meanwhile, opposition parties’ appeals for at least two tightly contested races elsewhere were also rejected.    

In Istanbul’s fashionable Cihangir neighbourhood, 60-year-old antique dealer Huseyin Guney expressed concerns that victory would be wrested away from the opposition.

"If Imamoglu has won justly, if it has been fated... If it isn’t, and if other avenues are pursued, our country’s image will really be shaken," he said.

Media organs close to Erdogan have claimed that AKP votes were stolen as part of an alleged "coup" against the ruling party, whereas international observers said the election was not fair.

Imamoglu, a 49-year-old former businessman and the little-known mayor of the Istanbul district of Beylikduzu, led a good-humoured campaign during which he promised to build bridges in the highly polarised city.

He even visited Erdogan in Ankara and asked for his vote too.

But he drew ire among AKP officials for signing a visitor's book at the mausoleum of Turkey’s founder in Ankara as "The Mayor of Metropolitan Istanbul" before the election results are finalised.

Istanbul - 4 April 2019

1. Various of people walking on a bridge over the Golden Horn, banners of Turkey's President Recep Tayyip Erdogan and ruling AK Party's Istanbul mayoral candidate Binali Yildirim (Turkish) 'Thank you Istanbul'

2. Woman sitting on the shore of the Golden Horn, Haghia Sophia in the background

3. Traffic on a street

4. Billboard of Turkey's President Recep Tayyip Erdogan and ruling AK Party's Istanbul mayoral candidate Binali Yildirim (Turkish) 'Thank you Istanbul'

5. Saban Ozmen's upholstery shop

6. Close of door 'Ozantik chair upholstery'

7. Saban Ozmen upholstering a chair

8. Close of staple gun

9. SOUNDBITE (Turkish) Saban Ozmen, Istanbul voter:

"People are fed up. I don't know, someone new brings excitement. I think he'll (referring to Ekrem Imamoglu) work (for the city.) The others thought they had settled by staying so long (referring to ruling AK Party.) It's not how it should be. A new excitement is necessary, someone who's willing to work. People have rights and I think that was being exploited."

10. Ozmen upholstering an ottoman

11. Close staple gun

12. SOUNDBITE (Turkish) Saban Ozmen, Istanbul voter:

"Everyone must show respect. I think he (Imamoglu) will be successful at the job. May it bring good fortune. God willing there will be no unrest."

13. Various of Huseyin Guney outside his antique shop

14. SOUNDBITE (Turkish) Huseyin Guney, opposition supporter:

"If Imamoglu has won justly, if it has been fated, it (Istanbul's mayorship) should be given to him. If it isn't, and if other avenues are pursued, our country's image will really be shaken. After all it's a local election and (Erdogan) still runs the country."

15. Various of people walking on the street

16. SOUNDBITE (Turkish) Erhan Celik, AK Party supporter:

"Whatever comes out of the vote, a full democracy is always the best for us, we defend a full democracy. Irregularities occur in elections, they have occurred, are occurring, and there are mechanisms against this and those will be set in place. But for example I didn't approve of what Imamoglu did: signing Ataturk's (mausoleum) visitor's log as 'mayor.' He could have waited a few more days, if it's his right (the mayorship.) Because you are nothing until you are given the (formal) mandate."

17. Wide of voter Semih Gokdemir having tea

18. Close of table

19. SOUNDBITE (Turkish) Semih Gokdemir, Istanbul voter:

"As I said, change is always good. The five-year process (length of mayoral mandate) will bring many things. During that time we'll have the opportunity to re-evaluate, favourably or unfavourably. But I believe that changes, different perspectives, will always move a place forward because competition is important. Monopolies are always problematic. At least now there's an environment of competition. We'll see the favourable and unfavourable aspects in the days to come but it's a hopeful situation for us."

20. Various of marine traffic on Golden Horn

Turkey's top election authority voided the mayoral election in Istanbul and ordered a rerun on Monday

The Supreme Electoral Board ruled Monday in favour of President Recep Tayyip Erdogan's governing party, which challenged the outcome of the March 31 election won by Ekrem Imamoglu.

A new vote in Istanbul will be held on June 23.

Ekrem Imamoglu of the opposition Republican People's Party, or CHP, had won the mayor's race in Turkey's largest city by a slim margin defeating the ruling party's candidate, former Prime Minister Binali Yildirim.

Erdogan's Justice and Development Party, or AKP, alleged that a series of election irregularities made the results invalid.

It pushed for an annulment of the vote after 17 days of appeals and repeated recounts failed to produce a different outcome.

The opposition has in the past questioned the independence of the electoral body, and has accused the ruling party of claiming fraud simply because it lost the vote.

Opposition newspaper Birgun also branded the decision as "coup," adding "justice has been suspended" and "democracy has been canceled."

Meanwhile, the lira extended its losses against the dollar on Tuesday amid the political uncertainty. The Turkish lira lost 2% of its value against the dollar, as the decision to renew the vote irked the markets. It had lost 10% over the last month.

Istanbul - 7 May 2019

1. Mid of a ferry approaching docks in Bosphorus

2. Close of ferry

3. Various of commuters getting off ferry

4. SOUNDBITE (Turkish) Hasan Basol, local resident:

"It is not reasonable at all that only mayoral ballots are cancelled and that ballot committee memberships are annulled because of a decision taken in 2008."

5. Mid of a newspaper stand

6. Close of Birgun newspaper reading (Turkish) "Coup, justice has been suspended and democracy has been cancelled"

7. Close of Sozcu newspaper, writing in yellow reading (Turkish): "AKP got what it wanted, Istanbul election is cancelled"

8. Close of Milliyet newspaper reading (Turkish) "To the ballot boxes again!"

9. SOUNDBITE (Turkish) Sevim Filiz, local resident:

"If there is any issue it should be re-run for things to be clear. I side with the renewal."

10. Mid of people entering ferry docks

11. SOUNDBITE (Turkish) Sevim Filiz, local resident:

"AKP (ruling party) is more effective, better, and has more services for the common people. That is why."

12. Various of people getting out of ferries

13. SOUNDBITE (Turkish) Ziya Yalcin, local resident:

"An election was won. Then from the same ballot box three (types of) votes are accepted yet a particular (mayoral candidate) type of vote was not accepted. From this point of view, it is a disgrace. Renewal is not good."

14. Mid of Seyfettin Gursel, professor of political sciences and economics, in his university study room

15. Close of Gursel writing

16. SOUNDBITE (Turkish) Seyfettin Gursel, professor:

"In (previous) 31 March elections there were voters from the (ruling party) AKP who did not go to the polls. It is important what they think about this situation, whether they will go to the polls and vote for (AKP's candidate) Binali Yildirim in the coming election. Moreover, it is also important what voters who already previously voted for Binali Yildirim think about this law scandal, whether they will have an adverse reaction. All that will affect the upcoming election."

17. Mid of a sign outside showing foreign currencies gaining advantage over Turkish Lira

18. Close of the sign

19. SOUNDBITE (Turkish) Seyfettin Gursel, professor:

"The Turkish Lira already lost almost 10% of its value during last month, and then lost again a similar value due to cancellation of the election. This is a currency shock, and it will negatively affect inflation. It would not have been so problematic had everything else been normal, but it is impossible for the central bank to hit its desired target for inflation in the current situation."

20. Various of Bosphorus