Gunfire and shelling rocked Sanaa early Tuesday as rival military forces battled each other on a third straight day of violence in the Yemeni capital in which 53 people have been killed, residents said.

After a lull in fighting that lasted only a few hours in the night, Sanaa residents awoke at dawn to the sound of automatic gunfire and shelling, with witnesses saying troops of dissident General Ali Mohsen al-Ahmar were clashing with those loyal to embattled President Ali Abdullah Saleh.

Security forces shot dead at least 31 people in Yemen on Monday, among them two children killed by snipers, protest organizers and medics said, as the United States called for restraint.

Organizers of anti-regime demonstrations in Sanaa said in a statement that 27 people were killed on Monday and that 942 people were wounded by gunfire over the past 48 hours, and that 47 are in critical condition.

Troops loyal to Yemeni President Ali Abdullah Saleh deployed in force in Sanaa on Sunday after opposition groups called new mass demonstrations demanding his ouster, an Agence France Presse correspondent reported.

The security forces closed off all access to the capital from Saturday afternoon while armed civilians loyal to the president also took to the streets, the correspondent said.

Four suspected al-Qaida members have been killed by army fire outside the southern Yemeni city of Zinjibar, most of which has fallen under the control of Islamist militants, a local official said Thursday.

The suspects were killed when their positions were hit by army shells in the villages of al-Khamla and Bajdar outside Zinjibar, the capital of the lawless Abyan province, the official told Agence France Presse requesting anonymity.

Yemeni President Ali Abdullah Saleh, recovering in Riyadh from bomb blast wounds, said a Gulf proposal for power transfer which he averted signing in the past should be treated positively.

The embattled veteran leader, whose regime has been facing protests since January, said his ruling General People's Congress party stresses the need to "continue to deal positively with the Gulf initiative," Saba state news agency reported Thursday.

Yemeni Republican Guards shot dead one protester and wounded three in the second-largest city of Taez on Thursday, medics said.

The Guards opened fire as thousands of people protested against the regime of President Ali Abdullah Saleh in central Taez, a flashpoint city south of the capital Sanaa, according to organizers.

Germany is serving as an intermediary in a bid to convince Yemeni President Ali Abdullah Saleh to stand down amid a popular revolt against his three-decade-long rule, a newspaper report said Thursday.

Germany's daily Frankfurter Allgemeine Zeitung reported in a front-page article that Berlin had sent an envoy to appeal to Saleh to accept a proposal by the Gulf Cooperation Council and head off further bloodshed in the country.

Yemeni President Ali Abdullah Saleh, who has been receiving treatment for blast wounds in Saudi Arabia since early June, will return "soon," deputy information minister Abdo al-Janadi said Saturday.

"The president is in good health. He will return to Yemen soon, but is awaiting the decision of his doctors," Janadi told a news conference, without specifying a date for Saleh's return.

Yemeni authorities arrested the head of a Shiite opposition party, Hassan Zaid, at Sanaa airport on Tuesday as he was headed for the Saudi city of Jeddah, his son said.

"My father was detained," Mohammed Hassan Zaid told Agence France Presse. "He was travelling to Jeddah when he was detained and not allowed to leave."

Ten Yemeni soldiers and 21 suspected al-Qaida militants were killed in clashes in south Yemen on Saturday, the defence ministry said on its news website.

Fierce clashes erupted in the city of Zinjibar, in Abyan province, between gunmen who have seized control of most of the city and besieged troops from the 25th mechanized brigade, a military official said on the 26Sep.net website.