The British embassy in the Turkish capital Ankara was closed on Friday for security reasons, according to the British government.
The government posted the one-day closure notice on its official Website on Thursday, but did not elaborate on the reasons for the decision.
It also advised against all travel to within 10 kilometres (6.2 miles) of Turkey's border with Syria and to the city of Diyarbakir in the country's southeast.
Turkey's state-run news agency says four people were detained following information about a possible Islamic State group attack on the German and British embassies in Turkey during the Muslim Eid al-Adha holiday, but investigators found there was no specific threat.
Authorities determined the suspects had no links to any extremist organisation and that there was no specific threat. But the UK and German embassies opted to stay closed as a precaution.
British Ambassador to Ankara Richard Moore wrote on his official Twitter account that keeping the embassy closed in that situation was an "appropriate precaution."