The parents, sister and three other relatives of the murderer of the Russian Ambassador Andrei Karlov's were arrested early this morning, according to security sources.
The relatives of the assailant Mevlut Mert Altintas were arrested in Turkey's southwestern province of Aydin and were taken to the provincial security directorate after questioning, security sources told the Anadolu Agency on condition of anonymity.
His roommate in Ankara was also arrested.
Altintas shot Karlov at an art gallery in Ankara yesterday. Karlov later died in hospital. Police killed the attacker in an operation that lasted around 15 minutes.
Security was tightened around Russia's mission in Turkey and around Turkey's mission in Russia, which the Russian Interior Ministry said is now under "round-the-clock" protection.
"The police stepped up security at Turkey's diplomatic missions in the Russian Federation," ministry spokeswoman Irina Volk was quoted as saying by the official TASS news agency.
Volk said Turkey's Embassy in Moscow and consulates in Russian cities are now under "round-the-clock" protection.
Newly appointed Turkish Ambassador to Russia Huseyin Dirioz said on Twitter that he was "deeply" saddened by the loss of life in yesterday's "despicable" attack.
"I strongly condemn this provocative attack," Dirioz said, adding that Russian Ambassador Andrei Karlov was an "exceptional" person who was helping to promote friendly relations between Turkey and Russia.
Dirioz said Turkey would not let the "heinous" attack cast a shadow over the friendship between the two nations.