Ankara- Turkish police have detained another suspect as part of the investigation into the assassination of Russian Ambassador to Ankara Andrei Karlov in December last year.

A total of three people, including two police officers, were detained in the case prior to Thursday’s arrest.

The unidentified detainee had maintained contact by phone with the ambassador’s killer.

Karlov was shot and killed by Mevlut Mert Altintas, a member of Ankara’s riot police force, at an art gallery exhibition opening in the Turkish capital on December 19.

The gunman was killed at the scene by the police.

Meanwhile, Turkish anti-terror police conducted more raids against hundreds of members of the Kurdistan Workers’ Party (PKK), which Turkey considers a terrorist group.

Security sources said that Turkish police arrested on Wednesday and Thursday around 843 people over alleged ties to the PKK.

Also Thursday, Turkish Prime Minister Binali Yildirim told a tourism conference that Turkey is “as safe as the United States.”

Speaking at the opening of the World Tourism Forum in Istanbul, Yildirim said the threat from terrorism was global.

“If we are talking about security, nowhere in the world is safe… terrorism does not recognize borders,” he said. “There is no place safe from terrorism. The fear and threat of terrorism is only useful to terrorists.

“Turkey is as safe as the United States, Istanbul is as safe as Paris,” he added.

A string of terror attacks across Turkey have threatened the country’s vital tourism industry, with the number of foreign visitors dropping from 36.8 million in 2014 to 25.4 million last year, according to the Culture and Tourism Ministry.