SANAA, Yemen - Yemen's president welcomed a proposal by Gulf Arab nations for him to step down to end the country's political crisis but indicated Monday he would do so only when his term ends in 2013 -- a condition already rejected by the protesters calling for his immediate exit.

President Ali Abdullah Saleh, a key U.S. ally in battling al Qaeda in his restive Arabian Peninsula country, has tried to cling to power despite two months of daily protests by crowds fed up with extreme poverty and a lack of political freedoms.

The government has responded with a crackdown on protesters, who were inspired by popular uprisings in Tunisia and Egypt, and clashes between demonstrators and security forces have been deadly at times. More than 120 people have been killed since the protests started in mid-February.

With Yemen sinking more and more into turmoil, the six-nation Gulf Cooperation Council -- a regional bloc of oil-rich Arab nations along the Gulf that includes powerful Saudi Arabia -- called on Saleh on Sunday to step down as part of a deal with the protest movement demanding for his ouster after 32 years.

Last week, Saleh rejected an earlier mediation offer by the GCC, which had invited Saleh and Yemen's opposition groups to Saudi Arabia for talks on its proposal.

In its Sunday offer, however, the GCC did not specify a timeframe for a transfer of power from Saleh to his deputy. It also included protections for him and his family from prosecution for crimes under his 32-year leadership -- another condition rejected by the opposition. The protesters' demands include seeing Saleh face justice.

Saleh's response Monday came in a statement from the presidential palace, stressing that the president "has repeatedly expressed no reservations to the peaceful and easy transfer of power within the constitution," which allows him to remain in office until the 2013 elections.

It said the GCC offer was a "basis for dialogue that will enable the country to avoid the misfortunes of chaos, destruction, disruption of security and public order and social peace."

Meanwhile, Saleh's supporters and pro-government groups went much further from the president's carefully worded statement, rejecting the GCC offer as a "flagrant interference in Yemen's internal issues."

According to the official SABA news agency, the group's denounced the GCC and said their move "goes against the will of the Yemeni people."

The anti-government protesters insisted Monday that Saleh step down and that he and his family members be put on trial.

Wassim al-Qarshi, an organizer of the daily protests in the capital Sanaa said the "people are determined to continue their protests in the public squares until their demands are achieved."

Keeping up the pressure, tens of thousands of protesters took to the streets Monday in the country's major cities, pushing for Saleh to go. In Sanaa, the demonstrators included a considerable number of women. There were also marches in the main streets of Taiz, Aden and elsewhere.