Two Italian military personnel were probably kidnapped in western Afghanistan.
The Italian Defense Ministry said that the two Italians had made no contact for several hours, that their families had been notified, and that an investigation was under way.
"We believe they have been kidnapped together with two Afghans," the ministry said in Rome. "The personnel were carrying out liaison activities with local civilian authorities. Searches are under way."
An official from the Italian embassy in Kabul said the two last spoke with officials at their base on Saturday night during "routine contact."
The two Italians, with their Afghan driver and translator, drove through a police checkpoint in the Shindand district of Herat province on Saturday, and they have not had any contact with anyone since, said Gen. Ali Khan Hassanzada, chief of police criminal investigations in western Afghanistan.
Taliban spokesman Qari Yousef Ahmadi told The Associated Press that he did not immediately know if Taliban militants kidnapped the four. Kidnappings by independent criminal gangs have increased around Afghanistan in recent months following reports that foreign governments have paid large sums to free kidnapped citizens.
The Afghan and Italian governments caused extensive controversy in March after five Taliban prisoners were freed in exchange for the release of a kidnapped Italian journalist.
The head of the Italian aid agency Emergency has said the Rome government also paid a US$2 million ransom last year for a kidnapped Italian photographer - a claim Italian officials did not deny.
Italy's Defense Ministry called the two Italians "military personnel" and the country's foreign minister called them "Italian functionaries," raising the possibility the two work as intelligence agents.
The embassy official said: "They have patrols like that, weekend patrols. They just disappeared after a while." The official spoke on condition of anonymity because of embassy policy.
The official said the two are warrant officers who were traveling "with a government interpreter on a military mission."
He said they were based in the city of Herat and were last seen in Shindand.
The disappearance of the two Italians was reported just before a high-level meeting on Afghanistan began at U.N. headquarters in New York co-chaired by U.N. Secretary-General Ban Ki-moon and Afghan President Hamid Karzai.
"There was note taken of the two Italians that have gone missing, and everyone expressed solidarity with the Italians on it, and President Karzai announced at the end of the meeting that he has some information as to where they might be," U.S. Ambassador to the United Nations Zalmay Khalilzad told two reporters afterwards.
Karzai told participants he would pass on the information to Italian authorities, Khalilzad said.
In Italy, the kidnaping immediately prompted calls by a few Communist lawmakers for Italy to withdraw its 2,160-strong force in Afghanistan - calls rejected by other lawmakers. Similar debates erupted in the past when other Italians were kidnapped in Afghanistan.
Last May, Shindand was the site of a major battle in which the U.S.-led coalition said its troops had killed 136 Taliban fighters, though Afghan officials at the time said scores of civilians also had died. The Afghan Ministry of Defense has since said that eight civilians were killed in that battle.
Herat police chief Juma Adil said the Italians were working with a reconstruction team in Herat that's associated with NATO's International Security Assistance Force.