Medics say Yemeni security forces have fired on anti-government protesters in the capital, Sana'a, killing at least one person.

Medics said the troops loyal to President Ali Abdullah Saleh also wounded at least 40 people Tuesday, as tens of thousands of protesters continued their call for the president to step down.

The troops later clashed with dissident soldiers in the capital.

Mr. Saleh said Monday he welcomed a U.N. Security Council resolution urging him to leave office and that he is ready for talks to be put in motion.

A Gulf Cooperation Council proposal offers Mr. Saleh immunity from prosecution if he hands power to a deputy within 30 days. On at least three occasions, Mr. Saleh has refused to sign the plan, saying he first wants international guarantees about a timetable for its implementation.

Also Tuesday, Yemeni security officials say a military plane crashed while landing at a base in the country's south, killing at least four people.

Officials said the crash in Lahej province was likely caused by a technical problem.

There were 15 people on board the plane when it went down, including eight Syrians and seven Yemenis.

Yemeni troops have been battling al-Qaida-linked militants in the south for months as political unrest also grips the country.