Yemen's president, under pressure from protesters to resign, told thousands of supporters on Friday that he will resist calls to leave office.
President Ali Abdullah Saleh described his opponents as "outlaws," while tens of thousands of anti-government demonstrators gathered nearby in the capital, Sana'a.
The dueling rallies crowded the streets following Muslim prayers after a Gulf Arab plan to end Yemen's political stalemate stalled in recent days.
The plan called for President Saleh to hand over power to a deputy and resign within 30 days of signing the initiative. It would have established a unity government that would have included opposition members.
Both the opposition and Saleh said last week that they agreed to the deal. But Saleh then said he would sign the deal only as leader of the ruling General People's Congress party, but not in his capacity as president - as required by the plan.
Officials with the six-nation Gulf Cooperation Council are trying to revive the pact, but Saleh on Friday told a rally he would "strongly defend the constitution."
At least 140 people have died in anti-government unrest since January
The rallies come after a suspected American missile strike on Thursday killed two brothers believed to be al-Qaida militants in a remote region.
Yemeni officials said the brothers Abdullah and Mosaad Mubarak died in Shabwa province, but they did not elaborate on how they were killed. Media reports quote tribal officials and witnesses as saying they suspected it was a U.S. missile strike.
Some information for this report was provided by AP, AFP and Reuters.