Yemen's government signed a cease-fire with a dissident general on Tuesday to try to end weeks of escalating bloodshed, but explosions and gunfire could still be heard in the north of the capital.
A government official said the deal between President Ali Abdullah Saleh's government and breakaway General Ali Mohsen would take effect at 3 p.m. (1200 GMT) on Tuesday, but residents of the Hasaba and Sofan neighborhoods in Sanaa said they heard explosions after that time.
After months of protests against Saleh's 33-year rule, a standoff between Saleh and an opposition of protesters, tribesmen and renegade soldiers tipped last month into bloody street fighting. Previous truce accords have failed to hold.
Earlier on Tuesday, security forces opened fire on a protest march in the capital Sanaa, killing two people, witnesses said. An opposition source said a third person was killed in shelling by Saleh's troops in the Sofan district.
In separate fighting between state forces and opposition fighters in the city of Taiz on Tuesday, eight civilians, including a child, were killed and more than 30 wounded, an opposition source said. The government said three members of its security forces were killed there.
Under the cease-fire deal mediated by a local committee, both sides agreed to dismantle armed checkpoints set up across the capital and release all those kidnapped during months of anti-government protests.
Saleh has defied months of demonstrations inspired by protests across the Arab world and refused to carry out a plan brokered by neighboring Gulf states to step down. The United States and Saudi Arabia fear the upheaval is giving al-Qaida local wing more room to operate in the poorest Arab country.
The truce agreement came four days after a United Nations Security Council resolution condemned violence in Yemen and urged Saleh to sign the Gulf initiative to hand over power. Violence has not abated.
Saleh welcomed the Security Council resolution on Monday. He has backed out of the Gulf initiative at the last minute three times and says he will transfer power only to "safe hands."
A Yemeni military plane crash-landed at an air base in Lahej province in the south, killing nine passengers, including eight Syrian engineers and one Yemeni engineer, according to doctors and army officials. A security official said a technical fault was probably to blame for the crash of the Russian-made Antonov plane, and the incident would be investigated.
Lahej borders Abyan province, where the Yemeni army is fighting to regain control of territory seized by suspected al-Qaida militants, who have benefited from political upheaval and weak central government control over parts of the country.
Late on Monday, an Uzbek doctor was abducted in the northern province and tribal stronghold of Maarib. A tribal source said the doctor had been kidnapped by tribesmen to put pressure on the government to release some jailed comrades.