ANKARA - An 18-member Russian delegation arrived in Ankara on Tuesday to investigate the assassination of Russian Ambassador to Turkey Andrey Karlov, local media reported.

The team, including one prosecutor and two defense attaches, will investigate the incident together with Turkish officials, private NTV reported.

The plane, which is expected to depart from Ankara Esenboga Airport on Tuesday afternoon, will take Karlov's body to Moscow after the accomplishment of procedures by Turkish and Russian authorities.

A ceremony is planned to take place at the airport to bid farewell to Karlov.

Meanwhile, Turkish police has arrested seven people over the Russian envoy's murder so far.

After six relatives and the roommate of Mevlut Mert Altintas, the assassin, were arrested early Tuesday, his uncle was released on judicial control.

Earlier, Altintas' parents, sister, and two other relatives were arrested in the southwestern province of Aydin.

On Monday, the Russian ambassador was delivering a speech at the Contemporary Arts Gallery in Ankara's central Cankaya district when Altintas opened fire, critically wounding him.

Karlov was rushed to a hospital where he was pronounced dead.