Four people have been detained in Turkey on suspicion of plotting acts against British and German diplomatic missions.

But authorities said they have found no links between the suspects and any terrorist groups, the state-tun Anadolu Agency said on Friday.

The arrests come as the UK embassy in Ankara closed on Friday with the Foreign and Commonwealth Office (FCO) citing security reasons but giving no further details.

The Germany embassy said on its website that its missions were only open for limited operations after a four-day public holiday this week.

Turkish authorities launched the investigation after intelligence about a potential Islamic State threat against the missions but found no terrorism links, officials said.

Turkey has been repeatedly targeted in the past by militants, both Islamist and Kurdish.

A suicide bomber at a wedding in the southeastern city of Gaziantep last month killed more than 54 people, including 22 children, the deadliest such bombing this year.

That attack is believed to have been carried out by Islamic State militants.

The British embassy in Ankara was closed between Monday and Thursday for the Eid al-Adha holiday this week, one of the two most importantfestivals of the Islamic calendar.

"The British Embassy Ankara will be closed to the public on Friday for security reasons," the foreign office said late on Thursday.

The FCO also advised Britons against travel to within 10 kilometres (6.2 miles) of the Syrian border and to Diyarbakir, the largest city in the mainly Kurdish southeast.

The city has been hit by waves of violence since the end of a ceasefire between the state and the outlawed Kurdistan Workers Party (PKK) last year.