Prime Minister Rafik Hariri (search) resigned, dissolved his Cabinet and made the surprise announcement Wednesday that he would not try to form the next government, dropping out of the political scene at a time when Syria's (search) role in Lebanon is being challenged by the United Nations.

Hariri, who has led Lebanon most of the time since the end of the civil war in 1990, has been in a rivalry with pro-Syrian President Emile Lahoud (search) for years.

The move could be political posturing to secure a stronger mandate from parliament that, should he ultimately accept the job, would better position him in the struggle with Lahoud. Declining now and accepting later, also could improve the standing of Hariri's parliamentary bloc ahead of elections expected in May.

Hariri submitted his resignation to Lahoud during a brief meeting in the presidential palace, his office said. The statement also said Hariri will not seek to lead the next government.

Lahoud accepted the Cabinet resignation but did not comment on Hariri's decision.

Hariri had initially opposed an amendment to the constitution to extend the president's term — a Syrian-backed move that drew international condemnation. But Hariri ultimately changed his stance and backed the amendment — leading most to expect he would be reappointed as prime minister when Lahoud's next presidential term begins in late November.

The U.N. Security Council has urged Syria, the main powerbroker in Lebanon, to end its political and military involvement in its tiny neighbor. The Lebanese parliament's extension of pro-Syrian Lahoud's term was a direct challenge to the Security Council, which also demands Syria withdraw its remaining 14,000 troops from Lebanon.

U.N. Secretary-General Kofi Annan (search) is to report every six months on Syrian compliance.

With all the pressure on Syria and Lebanon's pro-Syrian politicians, Hariri's extensive international contacts would have been crucial to settling matters. But he and Lahoud, political rivals for years, apparently failed to bridge their differences.

The dissolution of the Cabinet is traditional ahead of a new presidential term.