SANAA, Yemen — Tens of thousands gathered at Yemen's main university Thursday in a protest again President Ali Abdullah Saled, despite a promise made by the leader on Wednesday that he would step down in 2013 and that he would not pass power onto his son, Ahmed.

A similar number of protesters supporting the president gathered in the capital's main square.

In an apparent attempt to pre-empt growing protests and demands for his immediate resignation, Saleh, who has ruled Yemen for more than three decades, said Wednesday that he would not seek re-election in 2013.

He also said that constitutional amendments to allow him to rule indefinitely, which were proposed by his party, would be frozen, and April parliamentary elections would be delayed in order to allow for electoral reform.

“I present these concessions in the interests of the country which come before our personal interests,” Saleh said Wednesday morning in an emergency meeting of parliament. “No extension, no inheritance, no resetting the clock,” he added, making reference to proposals to abolish term limits.

Saleh’s announcement echoed that of fellow authoritarian ruler, Egypt President Hosni Mubarak, who said Tuesday night that he would not seek re-election in September. Mubarak’s announcement, however, did little to satisfy the hundreds of thousands of Egyptians calling for his immediate removal from office.

Like Egyptians, Yemenis were also not satisfied by Saleh’s concessions.

Saleh’s statement came just 24 hours before the planned “Day of Rage” that was called by the country’s opposition groups.

Opposition leaders said the protests would be the largest challenge to Saleh’s regime since he first took power 32 years ago.

Mohammed al-Sabri, spokesmen for the opposition coalition — known as the JMP — which includes Islah, the country’s largest Islamic party, as well as the Socialist Party and the Nasserite Party, said the demonstrations would go ahead as planned.

“These protests will exceed last weeks'. Thousands will be demonstrating in cities across Yemen calling for the president to go,” Sabri said.

Saleh also called on demonstrators to cancel “all planned protests, rallies and sit-ins,” but the opposition has dismissed those calls, calling his concessions too little, too late.

“Saleh’s call for dialogue is one thing but the demonstrations are something else,” said Mohammed al-Mutawakel, a leader for the opposition. “The opposition will take to the streets tomorrow with the people no matter what.”

Saleh’s promise resembles a similar one he made before Yemen’s last round of presidential elections in 2006.

“You are tired of me and I of you, it is time for change,” Saleh told parliament in 2005.

Saleh has been taking strides to try and defuse simmering tensions since the Tunisian uprising and the recent unrest in Egypt. After increasing the wages of the military and slashing incomes taxes, he announced Monday the creation of a fund to employ university graduates and to extend social security coverage.

He also said he would exempt university students from the rest of their tuition fees for this academic year.

Unemployment has been a primary criticism among protesters in Tunisia and Egypt. The same is true in Yemen, which has the highest unemployment rate in the region at 40 percent.

As the protests near, the atmosphere in Sanaa is tense. The streets are lined with soldiers preparing for tomorrow’s demonstrations and road blocks are in place across the city, an attempt to prevent the smuggling of weapons into the city, according to the Interior Ministry.

The protests Thursday are planned for Tahreer, the main square at the heart of the capital, but government authorities have already filled it with pro-Saleh supporters chanting slogans, dancing and waving Yemeni flags.

“We’re camping out here overnight, the square is ours,” said a pro-Saleh supporter who did not wish to be named.

In response, Yemen’s opposition has called for a last-minute change of venue, and the protests will now take place at the city’s main university. The opposition said it had been spreading news about the protest through leaflets and at mosques. They have also used a paid messaging service, provided by Sabafon, a large mobile-phone provider owned by Hameed al-Ahmar, a prominent member of the Islamic Islah party.

Saleh has promised that he will provide tomorrow’s protesters with water and that the army will not use live ammunition.

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