Turkey nabs six over killing of Russia envoy

Turkey has arrested six people in connection with the assassination earlier of Russia's ambassador to the country.

An off-duty police officer in civilian clothing shot down Andrey Karlov, the Russian envoy, as he was inaugurating a photo exhibition in the Turkish capital, Ankara, on Monday.

On Tuesday, the state-run Anadolu agency said the attacker's mother, father, sister and two other relatives were being held in the western province of Aydin, while his flatmate in Ankara had also been detained.

Kremlin spokesman Dmitry Peskov also said on Tuesday that Russian investigators had flown to Turkey earlier in the day to help probe the killing as per a mutual decision taken by Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan.

"Eighteen people will work in the group. The group will act in Turkey within the framework of the investigation into the murder," Peskov said.

After carrying out the murder, the assailant went on a rant caught on camera, which saw him bawling, "Don't forget Aleppo, don't forget Syria!"

However, a senior Turkish security official has said there are "very strong signs" that the gunman belonged to the network of the US-based cleric Fethullah Gulen.

The Turkish establishment accuses Gulen, Erdogan's ally-turned-archfoe, of orchestrating an abortive July coup.

The assassination, condemned by the Turkish and Russian leaders as an attempt to sour the bilateral ties, came as the countries are maintaining cooperation over the Syrian crisis. Turkey is partaking in talks on behalf of anti-Damascus militants, who had been holding the city until recently. Russia has been supporting the Syrian government and has been negotiating on its behalf.

Iran, the US, NATO, and other countries and world institutions have also condemned the assassination of the Russian ambassador.

US shutters embassy, consulates in Turkey

Meanwhile, The United States government has shuttered its embassy and consulates in Turkey following the attack.

The embassy made the announcement in a security message on Tuesday, noting that the US Consulate General in Istanbul and the US Consulate in Adana would be closed for normal operations on the day.

The White House condemned the attack in a statement, calling it a "heinous" and "unacceptable" assault.

"We stand united with Russia and Turkey in our determination to confront terrorism in all its forms," US National Security Council spokesman Ned Price said.

US President-elect Donald Trump also condemned Karlov's murder, saying the attack violated "all rules of civilized order."