More than 20,000 Yemenis filled the streets of Sanaa on Thursday for a "Day of Rage" rally, demanding a change in government and saying President Ali Abdullah Saleh's offer to step down in 2013 was not enough.
Opposition supporters drove around the Yemeni capital from early Thursday announcing with megaphones that the protests would now be held at Sanaa University, about two kilometers (1.2 miles) from al-Tahrir square where the demonstration had been planned.
They said the venue change was because "the men of the ruling party and their armed elements are holding Al-Tahrir."
From late Wednesday, dozens of armed men from President Ali Abdullah Saleh's General People's Congress were seen setting up tents and erecting portraits of the president in al-Tahrir Square.
Police were on Thursday trying to filter the influx of people into the square, some of whom carried banners reading, "We are with Ali Abdullah Saleh. We are with Yemen," and "The opposition wants to destroy Yemen."
Facing demands for him to quit, Saleh on Wednesday announced that he would not seek another term as president, and said he will freeze plans to change the constitution that would have enabled him to remain president for life.
He also said he was opposed to hereditary rule, a response to suspicion among critics that was grooming his eldest son Ahmed Saleh, who commands an elite unit of the Yemeni army, to succeed him as president.
In what appeared to be yet another bid to stave off the kind of mass anti-regime protests that have swept Tunisia and Egypt and which have rippled throughout the Arab world, Saleh also announced he would postpone controversial elections due in April.
Unimpressed, opposition groups said they would press on with their "day of rage."
"Thursday's demonstration will continue as scheduled," said Mohammed Kahtan of the Islamist Al-Islah (Reform) party.
Mohammed al-Sabri of the Common Forum opposition alliance said Saleh's call to halt protests was "unacceptable." However, he said the group would "discuss the president's announcement."
There have been clashes during previous protests against Saleh, including on January 29, when dozens of activists calling for his ouster fought with regime supporters in Sanaa. Plain-clothes police also attacked demonstrators.
Facing growing protests since last month's downfall of Tunisia's president Zine El Abidine Ben Ali and the wave of anti-regime protests in Egypt, Saleh urged the government to take urgent measures against unemployment.