Three U.N. workers who were held hostage in Afghanistan (search) met with President Hamid Karzai (search) on Wednesday, looking tired but happy a day after their release from nearly four weeks of captivity.

Philippine diplomat Angelito Nayan, Annetta Flanigan from Northern Ireland and Shqipe Hebibi of Kosovo held a private meeting with the Afghan leader in his palace in Kabul.

Smiling nervously, they later posed alongside Karzai for photographers, but made no comment at all on an ordeal which began and ended in still-murky circumstances.

Nayan, a traditional green Afghan robe draped over his shoulders, declined to answer reporters' shouted questions. All three left clutching a wrapped gift from the Afghan government.

"We are very glad that by the grace of God our two sisters and a brother who were taken by the hostage-takers, by the criminals, were released safe and sound," Karzai said. "The Afghan people were saddened and put in serious grief by this incident."

It was unclear when the three, who helped organize Oct. 9 presidential elections which Karzai won, would fly back to their home countries where friends and relatives await.

Armed men seized the three on a Kabul street on Oct. 28 in the first such abduction of foreigners since the Taliban fell in late 2001, suggesting anti-government rebels were adopting the tactics of Iraqi insurgents.

A Taliban splinter group claimed the kidnappings and said the Afghan government agreed to release 24 jailed comrades.

But Afghan officials insist they agreed to pay no ransom or free any jailed militants to secure their release. They have declined to identify the suspected kidnappers or to explain how they were freed.

The release prompted jubilation among fellow aid workers in Kabul's 2,000-strong expatriate community. But the United Nations and relief groups warned that much of the country remains dangerous for foreigners.

Tracts of Afghanistan are already off-limits to aid organizations because of a stubborn Taliban-led insurgency. Already this year, 24 aid workers have died in violence.

U.N. Secretary-General Kofi Annan, who spoke to the three released workers, said he was "profoundly relieved" their ordeal was over.

He said the world body would need to "strengthen the security of its staff in order to enable it to fulfill the organization's mandate to further peace, reconstruction and democracy in Afghanistan."

Paul Barker, the head of CARE International, one of the largest relief groups in Afghanistan, welcomed the peaceful outcome of the kidnapping but said it was unlikely to prompt aid groups to return to the troubled south and east of the country.

"Had it not ended this way, it would have been a big setback to a lot of reconstruction efforts here," Barker said. "There are still plenty of serious incidents in all corners of the country."