The British and German embassies in Turkey have been forced to shut amid fears of a militant attack.
The embassies in Ankara both stayed closed on Friday after intelligence warned of a possible threat during the festival of Eid al-Adha.
Four people arrested earlier this week as part of an investigation into the warning have no links to terror groups, the authorities say.
So-called Islamic State and Kurdish rebels recently carried out attacks.
British ambassador Richard Moore said on his Twitter account the closure was a "reasonable precaution".
However, apart from saying staff were working "closely and cooperatively" with Turkish authorities, he would not be drawn on the nature of the threat.
The embassy had been due to reopen on Friday after closing for the holiday.
The Foreign Office confirmed the embassy was shut "for security reasons". Germany took the added precaution of closing its schools and consulates across Turkey, according to Bild newspaper.
The German embassy in Ankara said it was offering limited services this week with its missions remaining "closed for any meetings".
Turkish state-run media say the four arrests - three in Ankara and one in Istanbul - were made on Monday, ahead of the holiday.
"Four people were detained in relation to a potential act against the two embassies," an official told Reuters news agency.
"Security remains at the highest level. We continue to cooperate closely and share information with the foreign missions."
It is unclear if they are still in custody.