World leaders have begun to react to the deaths of 39 people killed after a gunman opened fire with a rifle inside a packed Istanbul nightclub an hour after midnight on New Year's Day.

The Turkish club Reina is popular among foreigners.

Turkey's Foreign Ministry has said 15 of the people killed were foreigners. Another 69 wounded are being treated at hospitals. About 600 people were estimated to have been in the club.

British Foreign Secretary, Boris Johnson, called the shooting a "cowardly act of terrorism" and that the UK stands "shoulder to shoulder with our Turkish friends".

"It was supposed to be a night of celebration: terrorists turned it into one of violence, death, despair," wrote Martin Schulz, president of the European Parliament online. "My thoughts with Istanbul, Turkey," he added.

However, no terrorist groups have yet claimed responsibility for the attack. The gunman is still at large.

Witnesses claim opened fire with a Kalashnikov rifle after killing a police officer stationed outside the club.

Several terrorist attacks have hit Turkey in recent months. On Saturday (17 December) a car bomb killed 13 Turkish soldiers and wounded 48 in the Turkish city of Kayseri when it destroyed a bus carrying the soldiers.

A week earlier on Saturday, 10 December militant Turkish Kurds claimed responsibility for two bombs that killed 44 people and wounded 166. Among the victims were 36 police officers, at least eight civilians.