Large explosions shook an air base outside the Yemeni capital Sanaa, prompting authorities to shut the city's nearby airport.
Residents said they believed at least one shell had hit the al-Daylami base which is adjacent to Sanaa International Airport.
Flights were diverted to Aden airport in the south of the Arabian Peninsula country.
Yemen's capital has seen weeks of fighting between troops loyal to President Abdullah Saleh and tribesmen who back protesters demanding an end to of his 33-year rule.
Tribesmen in areas outside the capital have complained of months of attacks by the air force against their towns.
Tribal sources said earlier that four people, including three children, were killed overnight when troops shelled the tribesmen's region north of the capital, hitting a petrol station.
Thirteen others were wounded in the attack in the Arhab area, some 40km from Sanaa.
In the city of Taiz, south of Sanaa, a doctor said one civilian was shot dead and two were wounded by government forces who fired at a car. The incident occurred in a district where there have been clashes between government forces and pro-opposition tribesmen.
Months of anti-government protests have divided impoverished Yemen, pushing the Arabian Peninsula country to the verge of civil war and a humanitarian crisis.
Neighbouring oil giant Saudi Arabia and the international community fear growing lawlessness in Yemen is giving al Qaeda's regional wing scope to plan and potentially launch attacks in the region and beyond.
The ruling party is likely to name Saleh's deputy as its presidential candidate if a transfer of power is carried out under a Gulf-brokered power transition plan, Deputy Information Minister Abdu al-Janadi said on Sunday
The United Nations Security Council issued a resolution on 21 October deploring the fighting and calling on Saleh to leave office in line with the transition plan.
Elsewhere, Yemeni tribesmen have freed an Uzbek doctor they had abducted eight months ago in protest against an airstrike on their area
The man was handed to mediators late tonight and was on his way to the capital Sanaa.
It was not immediately clear whether the government had agreed to the kidnappers' demand to hold accountable those responsible for the airstrike against al Qaeda suspects in December 2009 which killed dozens of people.
In late February, tribesmen had lured Abdulhamid Jun out of the hospital where he worked in Shabwa province, an area of central Yemen where both separatists and al Qaeda militants are active, by asking him to treat relatives they said were injured.
