Turkish Police Detain 6 after Russian Ambassador Shot Dead

Media reports said on Tuesday the attacker's mother, father, sister and two other relatives were held in the western province of Aydin, while his flatmate in Ankara was also detained.

Police paced up and down behind a cordon on Tuesday morning outside the art gallery where the ambassador, Andrey Karlov, was shot. A crime scene investigation van was parked outside the building, according to Reuters.

The United States said its three missions in Turkey would be closed on Tuesday after a gun was fired in front of the US embassy in Ankara overnight. The embassy was near the art gallery where Karlov was shot and Turkish police detained a man over the incident, state media reported.

Russia's foreign ministry said on Tuesday the two countries' foreign ministers had underlined the need to put more effort into effectively fighting terrorism in a phone call overnight.

The Russian, Turkish and Iranian foreign ministers will meet in Moscow later on Tuesday to discuss the crisis in Syria. A Russian delegation was due to arrive in Ankara at 11 a.m. (0800 GMT) to conduct investigations into the attack.

Turkey faces multiple security threats, including from the Daesh (ISIL) terrorist group. A spokesman for the hardline group urged sympathizers around the world this month to carry out a fresh wave of attacks, singling out Turkish diplomatic, military and financial interests as preferred targets.

However, a senior Turkish security official said there were "very strong signs" the gunman belonged to the network of the US-based buisinessman Fethullah Gulen, who Ankara says orchestrated a failed coup in July. Erdogan has denounced Gulen as a terrorist, but the cleric, a former ally, denies the accusation, and has also denied any role in the assassination.