Anti-government tribesmen in Yemen have shot down a government warplane north of the capital, Sana'a, while tens of thousands of protesters demonstrated later Wednesday against President Ali Abdullah Saleh.

The jet went down about 40 kilometers from Sana'a in an area where tribesmen have been battling forces loyal to the president.

Tribal sources said their fighters shot down the plane using anti-aircraft weapons and captured the pilot.

Two days ago, tribesmen in the area overran a base of Yemen's elite Republican Guard, killing a commander and capturing about 30 soldiers.

Meanwhile, people protesting Wednesday in Sana'a waved flags and made peace signs as they marched and chanted against Mr. Saleh.

Other peaceful protests were reported in cities across the country.

Demonstrations against Yemen's embattled president have escalated over the past two weeks, with clashes between the rival sides leaving more than 100 people dead.

Mr. Saleh returned to Sana'a on Friday after a three-month stay in neighboring Saudi Arabia to recuperate from a June assassination attempt.