AFP - Two European women aid workers were kidnapped in Haiti last week but freed on Thursday, their organization, Medecins Sans Frontieres (Doctors Without Borders) told AFP.

"We are immensely relieved," spokesman Michel Peremans said, adding that both women -- whose nationalities he would not give -- were "safe and sound."

Peremans said the two were grabbed Friday in what was the first kidnapping of foreign aid staff since the January 12 earthquake in Haiti that killed more than 220,000 people and left 1.3 million people homeless.

He said the news had been kept secret until now so as not to "complicate" negotiations to free the women, whose lives had been "in danger."

"We confirm that there was a kidnapping," he said. The two women "were freed today."

Peremans would not go into details about the identities of the women, nor of their abductors.

Swiss media, however, reported that the two women were Swiss. The TSRinfo website reported that they were grabbed, with their Haitian driver, in the Petionville area of the city, where many aid groups are located.

The driver was freed after a short time and raised the alarm, TSRinfo said.

The Swiss embassy in Haiti could not immediately be contacted to confirm the information.

Peremans would not say if MSF had paid the kidnappers, but stressed that "it is not our policy to pay ransoms."

He also noted that MSF had been working in Haiti for years before January's disaster.

The organization has 400 foreign employees and 3,000 Haitians working for it in the country.

"We will see how we can keep working," Peremans said, adding that the security of MSF workers was of paramount importance.

"It's very important for us. We want to keep working in Haiti," he said.

Although MSF would not speak about the kidnappers, Haitian police and foreign security contractors have spoken of the danger posed by thousands of hardened criminals who escaped the main prison in the capital during the earthquake.

Most of them are believed to be hiding out in Cite Soleil, a city slum devastated by the quake, where police and UN peacekeepers struggle to impose the law.

The UN police said it had not been aware of the abductions -- explained by the fact that many of the aid groups in Haiti hire their own security details.