Sanaa: Yemeni soldiers loyal to President Ali Abdullah Saleh opened artillery fire late on Tuesday against armed fighters supporting protesters in the southern city of Taiz, in the latest resurgence of violence in the anti-Saleh stronghold.
"Government forces, from the hills and from security barricades, and from al-Thawra hospital and Freedom Square, they are shelling," Abdulkader al-Guneid, a resident in the town 200 km (125 miles) south of the capital Sanaa, told Reuters.
"There are all kinds of flashes and bangs, and we can hear it in the residential areas. Then, sometimes it is interrupted with an exchange of fire," he added.
Al Jazeera television said six people wounded in the shelling had reached hospital and more were expected but added that it was it was not immediately possible to determine the number of casualties.
State television blamed opposition fighters for starting the fighting and said four government troops had been wounded.
Taiz, and other opposition hubs, have been paralyzed by nearly nine months of protests to demand an end to Saleh`s 33-year rule.
In the capital Sanaa, mortar fire killed two civilians and wounded six in fighting between forces loyal to Saleh and troops siding with anti-government protesters.
A doctor said a mortar round hit a market in a district contested by government troops and those of rebel general Ali Mohsen, a former Saleh ally. One of the dead was aged 14.
The doctor said he had received death threats for helping the wounded and a bag of bullets was thrown into his yard as a warning.
"We are treating these protesters and civilians but the government wants to threaten us to stop us doing our job. Now they are threatening my family," he said.
Tensions are running high in the impoverished Arabian Peninsula country, which is awash with guns.
Last month in Sanaa, political deadlock gave way to a military showdown between Saleh loyalists and Mohsen`s forces. More than 100 people were killed in the fighting, most of them protesters caught in the middle.
Tens of thousands of protesters took to the streets again on Tuesday afternoon to draw attention to their demands ahead of an expected briefing by the United Nations` envoy to Yemen before the security council.
The opposition cast doubt on any future dialogue with the government, which it blamed for the apparent failure of mediation attempts by U.N. envoy Jamal Benomar, who left Yemen empty-handed on Monday.
"The dialogue with the regime has stopped and there is no form of dialogue after Saleh wasted all opportunities for dialogue, which led to the departure of the U.N. envoy," opposition spokesman Mohammed al-Sabri said.
Benomar spent two weeks in Yemen trying to broker a deal but left without announcing a breakthrough after days of mediating between the government and the opposition.
The opposition said a newly appointed general was killed on his way to a military base north of Sanaa, where he was due to take command after his predecessor was killed by tribal fighters last week. The defense ministry denied the report.
The upheaval is fanning global fears that weakening state control may help al Qaeda`s local wing expand its foothold in Yemen, which borders oil giant Saudi Arabia and lies near shipping routes through the Gulf of Aden and the Red Sea.
Awlaki`s remains buried
The remains of Anwar al-Awlaki, a U.S.-born cleric linked to al Qaeda, were buried over the weekend near the place where a CIA drone killed him and several comrades, a member of his family said on Tuesday.
The family member told Reuters Awlaki`s father traveled from the capital Sanaa to the northern province of al-Jawf on Saturday and identified his son`s dagger lying among scattered body parts, which they buried close by.
In Detroit, jury selection began on Tuesday in the trial of a Nigerian man accused of trying to blow up a U.S.-bound plane in 2009, who has been linked to Awlaki and al Qaeda`s Yemen-based wing.
Yemen`s army is fighting to regain territory lost to militants in the south, notably in Abyan province, where al Qaeda-linked Islamist fighters control the city of Jaar and other locations.
At least 10 militants were killed in an air force raid in the Jaar area on Tuesday, residents and a local official said.