"Four military police officers and two civilians were injured in a clash between security forces and unidentified armed men in a southern Yemeni city on Monday," police sources said.
According to the sources, the gunbattle broke out after police forces tried to disarm the men armed with AK-47 rifles in a marketplace in Ja'ar in the southern province of Abyan.
Police forces were acting as part of a campaign to enforce a ban on carrying weapons in main cities.
One of the injured police officers was in critical condition and he was admitted to a hospital in the southern port city of Aden.
"The armed men, believed to be tribesmen, fled the scene unharmed, and a police manhunt was launched to arrest them," a security source in Abyan said.
"Yemeni Police have confiscated more than 100,000 firearms since the nationwide campaign to enforce a ban on carrying weapons in cities began last August," the interior ministry said last week.
The ban, that includes bodyguards of high-ranking officials, legislators and influential tribal chieftains, is aimed at reducing the visibility of arms that discourage tourism and investments in the country.
Police officials have said the campaign helped decrease the rate of domestic crimes by 40 percent during the last four months of 2007.
Authorities have in recent years tried to crack down on people carrying arms, but their efforts have met with little success.
In 2005, the government embarked on a scheme to collect heavy weapons from tribal communities or arms traders, spending $44 million to buy back weapons, according to officials. The effort, however, floundered as a result of inadequate funding.
Unofficial estimates put the number of firearms in circulation in Yemen at around 60 million. A UN-sponsored small arms survey, released last August, concluded that Yemenis own between six and 17 million firearms.