A French woman and two Yemenis working for the International Committee of the Red Cross have been abducted in the southern Yemeni province of Lahej, Western diplomatic and Yemeni officials say.

A local official in Lahej said the woman had been taken from her vehicle with along with the Yemenis by armed men on Tuesday demanding the release of prisoners held by Yemeni authorities in the nearby southern port of Aden.

"She was seized from her vehicle near a small village in Lahej," a Western diplomat said, declining to give further details.

They had been travelling to distribute aid to a camp housing Yemenis displaced from another southern province, Abyan, where fighting between Islamists who have seized chunks of territory and Yemeni troops has forced tens of thousands of people to flee.

Kidnappings of foreigners in Yemen are common, often in the context of grievances by tribes or regional factions with central government authorities, whose hold over parts of the south is tenuous.

Three French aid workers held hostage by Yemeni tribesmen for over five months were freed earlier this month after mediation by neighbouring Oman, which tribal leaders said paid their captors ransom on behalf of the French government.

Ten months of protests demanding the end of President Ali Abdullah Saleh's 33-year rule have paralysed the country, and its political deadlock has reignited conflicts with separatists and Islamists.

Neighbour Saudi Arabia and the US, which made Saleh a cornerstone of its campaign against al-Qaeda, have urged him to transfer power in line with the terms of a handover plan crafted by Yemen's resource-rich neighbours.

Saleh has thwarted that plan, now echoed by a UN Security Council resolution, three times already.

A UN mediator trying to implement the deal said on Tuesday it had been agreed but that details related to its signing were still unresolved.