Updated

SANAA, Yemen -- Yemeni government warplanes and artillery pounded several villages of anti-government tribes north of the capital on Tuesday, killing at least three people, a senior tribal leader said.

Sheik Ali Youssef of the Naham tribe said that Republican Guard forces, which are commanded by embattled President Ali Abdullah Saleh's son, began bombarding the villages scattered in the Naham mountain area, some 20 miles north of Sanaa, on Monday, continued throughout Tuesday.

Youssef said at least three people were killed, 48 houses destroyed and hundreds of people forced to flee their homes in the assault.

The Naham mountain area has seen clashes between government forces and anti-Saleh tribes since Yemen's popular uprising against Saleh's rule began in mid-February. Tribesmen there frequently have prevented government troops stationed at bases in the area from deploying to the capital.

Also Tuesday, Yemen's Defense Ministry said government forces killed nine Al Qaeda suspects in clashes in Zinjibar, the capital of Abyan province in southern Yemen.

Residents in southern cities have criticized government forces for showing little appetite to face down the Islamist extremists in the south. The militants have already seized Zinjibar and now are operating openly, training with live ammunition and controlling roads with checkpoints.

Their gains have fueled fears that they are successfully exploiting the power vacuum and turmoil caused by a popular uprising against Saleh that began in February. The revolt gained momentum when a coterie of the president's close aides, military commanders and Cabinet ministers joined the protesters.

Saleh, who has ruled Yemen for nearly 33 years, left for neighboring Saudi Arabia on June 5 to treat severe wounds he suffered when his compound in the capital Sanaa was attacked. It is not clear when -- or if -- he will return, deepening uncertainty in the poor nation at the southern corner of the Arabian Peninsula.

Also on Tuesday, a U.N. delegation has arrived in Yemen and held a meeting with the country's acting president, Abed Rabbo Mansour Hadi, the vice president. The delegation is a fact finding mission into human rights violations.