MINSK, Belarus: Ukraine and the Russian-backed rebels have signed a cease-fire deal that starts in less than two hours, a European official at the talks said Friday.

A senior rebel leader however said the deal reached with Kiev on Friday did not change the desire of pro-Russian rebels in eastern Ukraine to break away from Kiev.

“The cease-fire does not mean the end of (our) policy to split (from Ukraine),” Igor Plotnitsky, the leader of the self-proclaimed Luhansk People’s Republic, told reporters.

The announcement by Organization for Security and Cooperation’s Heidi Tagliavini came as representatives of Ukraine, Russia, pro-Russian rebels and the OSCE in Europe met in the Belarusian capital of Minsk. She said the cease-fire would start at 1500 GMT (11 a.m. EDT).

Since mid-April, Moscow-backed separatists have been fighting government troops in eastern Ukraine in a conflict the UN estimates has killed nearly 2,600 people.

On Thursday, a NATO military officer told The Associated Press that the ranks of Russian soldiers directly involved in the conflict have grown.

Earlier Friday, Associated Press reporters heard heavy shelling north and east of Mariupol. The key southeastern port of about 500,000 lies on the Sea of Azov, between Russia to the east and the Crimean Peninsula to the west, which Russia annexed in March. The shelling appeared to indicate that rebels had partially surrounded the area and were probing its defenses.

The seizure of Mariupol would give the rebels a strong foothold on the Sea of Azov and raise the threat that they carve out a land corridor between Russia and Crimea.

If that happens, Ukraine would lose another huge chunk of its coast and access to the rich hydrocarbon resources the Sea of Azov is believed to hold.