Port-au-Prince : Two European aid workers with Doctors Without Borders in quake-hit Haiti were kidnapped and held for nearly a week before being freed early on Thursday, the international medical charity said.

"Two of my colleagues, two women, were abducted last Friday. They were released early this morning... they are in good health and in good shape," said Michel Peremans, spokesman in Haiti for Doctors Without Borders/Medecins Sans Frontieres.

Citing privacy considerations, he declined to give their identities or details of the circumstances of the kidnapping, which occurred in Port-au-Prince.

One of the women was Belgian and the other from the Czech Republic, Peremans told Reuters.

He declined to say whether a ransom had been asked for or who the kidnappers were.

"It is not our policy to pay any ransoms," Pere-mans said.

It was the first known kidnapping of foreign nationals in Haiti since the catastrophic earthquake on January 12 that wrecked Port-au-Prince and surrounding towns.

The incident was expected to raise security concerns among the thousands of foreign aid workers and soldiers who have flocked to Haiti since the quake in a huge international relief operation, as well as journalists.

There were fears that the kidnapping could lead to copycat abductions.

Peremans said Doctors Without Borders had been working in Haiti, the Western Hemisphere's poorest country, for 19 years and wanted to continue.

The charity has 400 expatriates and 3,000 locals working for it in Haiti had provided care to 40,000 people since the quake, he added.

"There are immense needs. We think our assistance is essential, so we want to stay, but of course we will review how we can work in Haiti," he said.

Haitian President Rene Preval has said up to 300,000 people may have been killed by the earthquake, and more than a million people were left homeless, most of them poor.

Although the small Caribbean nation has a bloody history of political instability and social unrest, United Nations and US military commanders involved in the post-quake aid operation say security has remained generally stable.

Widespread looting

Nevertheless, significant looting followed the quake and aid groups reported some cases in which gunmen had attempted to hold up food convoys, which travel with military escorts.

In past years, kidnappings were common in Haiti.

Several thousand convicted prisoners have escaped from quake-damaged jails, and most of them are still at large.