President of Ukraine Petro Poroshenko speaks during the news conference in Riga, Latvia April 4, 2017. REUTERS/Ints Kalnins

LONDON (Reuters) - Ukraine’s President Petro Poroshenko on Wednesday called for Western sanctions on Russia to be maintained in order to keep the Kremlin in line and to ensure the success of Ukraine’s own economic reform program.

“We need firm support for Ukraine reform... To proceed, sanctions should stay firm on Russia - this is the only mechanism to keep Russia at the negotiating table,” Poroshenko told a conference in London.

Russia has been punished with economic sanctions in retaliation for its annexation of the Crimea region in 2014 and its alleged role in the conflict in eastern Ukraine.