The leader of Ukraine's Radical Party, Oleh Lyashko, has announced his party is quitting the coalition government.
Lyashko said on September 1 that the right-wing party opposes a constitutional amendment that aims to give more autonomy to areas controlled by pro-Russian separatists in eastern Ukraine.
Ukrainian nationalists strongly oppose the measure, fearing it would threaten the country's sovereignty.
Lyashko called for a national referendum on decentralization to be held in October along with local elections.
The deputy head of President Petro Poroshenko's bloc in the parliament, Ihor Kononenko, said the Radical Party's exit will not affect the coalition's work.
The Radical Party holds 21 votes in the parliamentary coalition of 302 seats.
The bill, which was presented by President Petro Poroshenko and is part of Kyiv’s obligations under the February Minsk peace accords, was tentatively approved by parliament on August 31.
Based on reporting by UNIAN and Interfax