President Lech Kaczynski on Monday appointed his identical twin brother, Jaroslaw, as the new prime minister, the presidential Web site said.

The move came after Prime Minister Kazimierz Marcinkiewicz and his government formally resigned, clearing the way for Jaroslaw Kaczynski to form a new government.

His resignation came in a meeting with President Kaczynski two days after the governing Law and Justice party decided to replace him with Jaroslaw Kaczynski, the party chairman.

"I thanked him for his very good governing," Lech Kaczynski said in a brief statement after a 45-minute meeting with Marcinkiewicz at the presidential palace.

President Kaczynski accepted Marcinkiewicz's resignation and asked him to fulfill the duties of prime minister until the new government is sworn in, which could take several days.

Marcinkiewicz departed amid reports of disagreements between him and Jaroslaw Kaczynski, who was widely regarded as the power behind the scenes of the outgoing government. The rift had reportedly widened recently over conflicting views of Poland's economic policy.

Marcinkiewicz met with his Cabinet for the last time before heading for the president's office to tender his resignation. Most of his ministers are expected to stay in the new government.

Jaroslaw Kaczynski has said his future Cabinet would continue the pro-social welfare policies of the previous government. Law and Justice sealed a coalition deal in May with two Euro-skeptic parties — the farm-based Self-Defense and the Roman Catholic League of Polish Families.

In one expected change on Sunday, the new prime minister picked Stanislaw Kluza, a pro-market economist who served over the past two months as a deputy finance minister and head of the ministry's research department, to head the Finance Ministry in his future Cabinet.

Jaroslaw Kaczynski said at a news conference that Kluza would continue the policies of his predecessor, Zyta Gilowska, who — until she resigned two weeks ago — was seen as the key guarantor of fiscal responsibility in Poland's government.

Marcinkiewicz will now run as the Law and Justice party's candidate for mayor of Warsaw in fall elections.