Ukraine's parliament on Monday voted for constitutional changes to give its eastern regions a special status that it hopes will blunt their separatist drive, but divisions among pro-Western lawmakers suggested the road to making them law will be rough.

At a rowdy session, 265 deputies voted in favor in the first reading of a "decentralization" bill, backed by President Petro Poroshenko's political bloc and his government — 39 more than that required to go through.

But many coalition allies, including former Prime Minister Yulia Tymoshenko, spoke against the changes and it is open to question whether Poroshenko will be able to whip up the necessary 300 votes for it to get through a second and final reading later this year.

Approval of legislation for special status for parts of the Donetsk and Luhansk regions, which are largely controlled by Russian-backed separatists, is a major element of a peace agreement reached in Minsk in February.

Though a cease-fire is under pressure from sporadic shelling and shooting which government troops and rebels blame on each other, Western governments see the deal as holding out the best possible prospect for peace and are urging Ukraine to abide by the letter of the Minsk agreement.