BUCHAREST, Romania (AP) — Romania's ruling party plans to submit a vote of no-confidence against its own government Sunday after it withdrew its support for the prime minister.

Prime Minister Sorin Grindeanu has refused to quit, sparking a political crisis.

The center-left Social Democratic Party convened lawmakers to read out the motion against the government, a day earlier than scheduled, in its efforts to remove Grindeanu, accused of not implementing the party's program. Parliament will vote Wednesday on whether to dismiss the government.

Grindeanu, in office since January, denies that he has underperformed. He claims the powerful party chairman, Liviu Dragnea, who can't be prime minister because of a conviction in 2016 for vote rigging, wants to install a party loyalist as premier.

Ex-Prime Minister Victor Ponta, an ally of the prime minister, called for talks with Dragnea to resolve the crisis and avoid a no-confidence vote, which he called "an atomic war between the Social Democrats and the Social Democrats."

Ponta said the party in-fighting would benefit President Klaus Iohannis, a political rival, who nominates a premier who is then approved by Parliament.

The Social Democrats and their political allies need 233 votes out of a total of 465 seats to remove the government.