Yemen's foreign minister has warned that insecurity resulting from months of mass protests and political unrest could delay presidential elections planned for next month.

"If we don't deal with the security challenges ... it might be difficult to hold elections (as scheduled) on February 21," Abu Bakr al-Qurbi said in an interview with Al-Arabiya television Tuesday.

His comments came after news that Al-Qaeda militants had taken control of a Yemeni town just 130 kilometres (80 miles) southeast of the capital, marking a significant military advancement towards Sanaa by the extremist group.

Qurbi, who is accompanying Yemeni Prime Minister Mohammed Basindawa on a tour of Gulf states, said the security situation in the restive country was "worrisome" and that the new unity government could not resolve the problems "without the cooperation of Yemen's political parties," including the former ruling General People's Congress.

A brutal crackdown on mass anti-government protests and streets battles between government forces and the opposition since January of last year have left hundreds dead and weakened the central government's ability to enforce control over much of the country's outlying provinces.

On Sunday, a force of some 1,000 militants swept into Rada, and in just a few hours took full control of the town, forcing security forces to retreat from their military positions in and around the city.

Al-Qaeda also controls several other towns and cities in the country's restive south, including Abyan province's capital Zinjibar.

In the north, Shiites and Sunnis have been engaged in fierce battles in recent months, raising sectarian tensions and leaving dozens dead.

Vice President Abdrabuh Mansur Hadi, who became Yemen's de facto ruler after embattled President Ali Abdullah Saleh handed over his power under a Gulf-sponsored transition plan, announced the February election date last November in a decree.

Hadi is expected to be the sole candidate in the poll and will take over as consensus president for a two-year interim period, after which parliamentary and another round of presidential elections are to be held, as stipulated by the Gulf-mediated plan.