Update: 14.20pm: Turkish police have detained four Islamic State suspects as part of an investigation into a possible attack on the US Embassy in Ankara, the country's state-run news agency has reported.
The embassy was closed today over an unspecified security threat.
The Anadolu Agency said police detained four Iraqi nationals in connection with the threat against the embassy. Two of them were detained on a bus at a security check on a road linking the Black Sea city of Samsun to Ankara. Two others were detained in Samsun.
12pm: The Ankara chief prosecutor's office said in a statement that all of the suspects captured in the police operation were foreign nationals.
They were allegedly trying to recruit members for the extremist group and were in contact with people in "conflict zones", the statement said, without providing further details.
The US embassy said on its web page late last night that the mission would be closed due to a security threat and urged US citizens to avoid the embassy as well as large crowds. It also advised citizens to "keep a low profile", adding that it would announce its reopening once it resumes services.
It was not clear if the embassy's closure was related to today's police operation. But the Ankara governor's office said authorities had "reviewed" security in the capital and had taken additional measures, following intelligence provided by US "sources" about possible attacks against the embassy or where Americans are staying.
Security was high outside the embassy today, and police searched pedestrians before allowing them to enter a street where the main gate is located.
In 2013, a suicide bomber detonated an explosive in front of the US Embassy in Ankara, killing himself and a Turkish guard. Turkish officials blamed the attack on domestic leftists.
Turkey suffered deadly terror attacks in 2015 and 2016 carried out by IS or Kurdish rebels. An attack at a luxury Istanbul nightclub during New Year celebrations on January 1st, 2017, killed 39 people.
- Press Association