A preliminary ceasefire agreement between the Ukrainian government and pro-Russian rebels has been signed, the BBC reports.

Ukrainian President Petro Poroshenko announced at the Nato summit in Wales this morning that a truce would begin at 3pm GMT today.

The agreement is part of a seven-point peace plan proposed by Russian President Vladimir Putin on Wednesday during talks in Minsk.

Nato secretary general Anders Fogh Rasmussen is said to be "suspicious" about Putin's plan, however.

According to the Guardian, "Rasmussen said he had seen similar moves before by Russia that had been smokescreens, but he would welcome a serious political settlement."

A spokesperson for Nato yesterday confirmed that the military alliance "stands with Ukraine" and denounced Russia's influence as "destabilising" – calling for Putin to "pull back" troops.

Rasmussen urged Russia "to step back from confrontation and take the path to peace," while Poroshenko blamed "Russian aggression" for "brutally undermin[ing]" security in Ukraine.

New sanctions against Russia are to be announced at the summit today.