SANAA, Yemen - A regional bloc of oil-rich Arab nations along the Gulf, including powerful Saudi Arabia, called on Yemen's president Sunday to give up power as part of a deal with the protest movement demanding for his ouster after 32 years, a Gulf diplomat said.

Keeping up the pressure, tens of thousands of protesters marched in the capital, Sanaa, on Sunday, a day after renewed clashes between demonstrators and security forces there. Witnesses said police fired a barrage of tear gas late Saturday and that many demonstrators suffered breathing problems.

The statement, by foreign ministers of the six-nation Gulf Cooperation Council meeting in the Saudi capital, was effectively a call for President Ali Abdullah Saleh to step down, something he has refused to do. The bloc repeated an offer to mediate between Saleh and his opponents, said the diplomat, who requested anonymity because of the matter's sensitivity.

The plan offered by the bloc would have Saleh resign in exchange for immunity from prosecution.

The embattled president, once a key U.S. ally in the war against the al-Qaida terror network, has tried to cling to power despite two months of near-daily protests calling for his resignation.

Last week, he rejected an earlier mediation offer by the Gulf Cooperation Council, saying the group was meddling in Yemen's affairs. The council had invited Saleh and Yemen's opposition groups to Saudi Arabia for talks on its proposal for the president to hand over power to his deputy in return for promises that neither he nor his family would be prosecuted for any crimes committed under his leadership.

On Saturday, a senior adviser to Saleh met in Riyadh with the Saudi foreign minister, a sign that negotiations are continuing.

The council consists of Saudi Arabia, the United Arab Emirates, Qatar, Oman, Kuwait and Bahrain.

In rejecting the initial mediation offer, Saleh appeared to have been particularly ruffled by a comment by Qatar's prime minister last week that "we hope to reach an agreement that includes the resignation" of Saleh.

Saleh has offered to step down at the end of this year if an acceptable transfer of power is reached, but the opposition fears he is just stalling for time.

Anti-government protests inspired by popular uprisings in Tunisia and Egypt erupted in Yemen in early February, and more than 120 people have been killed since then in clashes between protesters and security forces.

On Sunday, demonstrators in Sanaa initially planned to march to the United Nations mission, which is not far from the presidential palace. However, they stopped short, fearing a violent government response and eventually returned to their base outside Sanaa's university.

The southern port city of Aden was paralyzed for a second day Sunday, with government offices, schools and shops closed as residents responded to the opposition's call for civil disobedience.

On Saturday, hundreds of thousands held rallies across the country. In Sanaa and the southern city of Taiz, protests turned violent and the director of a field hospital in Taiz said 580 people were injured Saturday.