Ukrainians have begun marking the 27th anniversary of the Chernobyl nuclear disaster with a midnight vigil.

Thousands of people arrived to pay their respects to those who were killed during and after the meltdown.

Thirty people were killed immediately when the nuclear reactor exploded on April 26 1986.

To seal off the damaged reactor and clean up the area, 100,000 Russians were sent to Chernobyl, but it was reported their protective suits were inadequate and some of them received a lethal dose of radiation.

According to Ukrainian government figures more than 4,000 of those who took part in the Soviet clean-up operation died as a result, though some say the actual figure is much higher.

The blast resulted in radioactivity being spread right across Europe. A lethal radioactive cloud poisoned 150,000 square kilometres of Ukraine and neighbouring Belarus.