World Bulletin/News Desk

At least 33 people have been killed in central Yemen in fighting in the past two days between Shi'ite Muslim Houthi fighters trying to expand their control and Sunni tribes allied with al Qaeda, residents said on Wednesday.

Separately, at least seven suspected militants were killed Wednesday in a drone strike that targeted their car in the southern Yemeni province of Shabwah, a local official said.

"A drone believed to be American hit a car carrying suspected Al-Qaeda militants in Al-Houta area in Shabwah, leaving seven of them dead," the official told Anadolu Agency on the condition of anonymity.

The bodies were badly charred in the car explosion, he added.

The expansion of the Houthis, who hail mainly from northern Yemen, has unsettled Sunni tribes in central al-Bayda province, threatening to provoke sectarian conflict.

Residents reported intense fighting in the Qifa area, home to powerful al-Bayda Sunni tribes who joined hands with the local al Qaeda wing, Ansar al-Sharia, to halt the Houthi advance.

In the city of Radda in the same province, which fell to the Houthis earlier this month, a car bomb apparently targeting a local tribal leader allied with the Houthis was blown up safely before it reached its intended destination, residents said.

They said the vehicle was halted by a security barrier erected some distance from the home of Sheikh Mohammed Muqbel al-Aywei and his followers blew it up without casualties.

Yemen, a U.S. ally which shares a long border with the world's top oil exporter, Saudi Arabia, has been engulfed in political turmoil since mass protests ousted its veteran president, Ali Abdullah Saleh, in 2011.

The Houthis, who captured the Yemeni capital Sanaa almost without a fight in September and forced the government to resign, are continuing to expand across the country despite the formation of a new government bringing in supporters of the group and representatives of southern Yemeni separatists.

The Houthis have objected to some members of Prime Minister Khaled Bahah's new team, saying they do not meet criteria agreed in a September power-sharing deal.

On Monday, two people were killed in a clash between Houthi fighters and security guards at Sanaa airport over who has the right to control security at the terminal.