SANAA (AFP) -- Four French nationals kidnapped by Yemeni tribesmen more than two weeks ago have been freed and are well, Yemeni and French officials have revealed.

A security official confirmed the Frenchmen, who were seized on September 10 in the town of Ataq, in Shabwa province southeast of Sanaa, had arrived in the Yemeni capital.

"The four French (tourists) have arrived by helicopter at the military base" next to the city's airport, the official told AFP, requesting anonymity. The French embassy in Sanaa also confirmed their release.

Foreigners are frequently seized by Yemen's powerful tribes for use as bargaining chips in disputes with the central government. More than 200 have been abducted during the past 15 years.

Lawmaker Awadh Bawazir, a tribal notable who has in the past been involved in mediating the release of Western hostages, told AFP earlier that he had seen the French tourists after they had been released.

The state-run Saba news agency said earlier that the tribesmen had released the tourists, who were "in good health," according to its correspondent in Shabwa.

They were "released following negotiations with the captors and tribal mediation, not by force," it said, quoting a security official in the region.

The Saba news agency report gave no other specific details about their release, but an interior ministry official said security forces were still looking for the captors.

On Sunday, newly re-elected Yemeni President Ali Abdullah Saleh had said the four tourists would be released "within hours".

The kidnappers had been demanding the release of relatives held by the authorities. They previously briefly held a German family and accused the authorities of reneging on the agreement that paved the way for their release. But Saleh, who won another seven-year term as president, said last week that the kidnappers "want to blackmail us" and that "serious and firm measures will be taken against the kidnappers."

The day before Yemen's presidential election last week, Saleh had said the hostages would be freed "by the end of the week".

Tribal leaders involved in the negotiations with the hostage-takers had said a deal on offer for the Frenchmen's release focused on a personal pledge from the president to address their demands after the election.

Mediators had sought to secure the hostages' release with an offer of substitute hostages from the families of provincial officials, but the deal fell through at the last minute after one of the officials declined to deliver his son as promised.

The five relatives whose release the kidnappers are seeking would be transferred to the capital from the southern province of Abyan where they are currently being held pending the president's decision, one of the negotiators told AFP last week.

Of the more than 200 foreigners abducted in Yemen in the past 15 years, all have been freed unharmed except for three Britons and an Australian seized by Islamist militants in December 1998. They were killed when security forces stormed the kidnappers' hideout.