BUCHAREST, Romania — About 10,000 people marched through Romania’s capital and other cities on Sunday to protest a government proposal to pardon thousands of prisoners, a move critics said would set back anticorruption efforts.

Protesters massed in Bucharest’s University Square called the ruling Social Democratic Party ‘‘the red plague.’’ They later marched to Victory Square, where the government has its main offices.

Premier Sorin Grindeanu has requested an emergency ordinance allowing the government to pardon prisoners to ease prison overcrowding. On Sunday, he said the protests had been ‘‘politicized’’ and criticized President Klaus Iohannis, who took part in a similar protest a week ago.

Critics say the proposal would benefit party allies convicted of corruption. Romania’s top prosecutor has criticized the plan.

It would primarily affect people serving sentences of fewer than five years, except those convicted of sexual or violent crimes.