BEIRUT, JUNE 2 -- Syrian Vice President Abdul Halim Khaddam declared tonight that the assassins of Lebanese Prime Minister Rashid Karami, if found, will be severely punished.

Khaddam spoke while visiting Tripoli, in northern Lebanon, the home of Karami, a Sunni Moslem political leader who was Syria's most influential ally in Lebanon. He was killed yesterday by a bomb aboard his military helicopter. Syria has several thousand military and security forces in Lebanon, many of them in and around Tripoli.

Meanwhile, Moslem leaders accused the Christian militias of masterminding the explosion, which wounded all 14 officials and military personnel aboard the helicopter that was bringing Karami back to Beirut from a visit to north Lebanon.

"We are confident that the sinful hand that carried out this crime will be severed and it will receive harsh and painful punishment," Khaddam declared after offering his condolences to Karami's family. The official arrived in Lebanon at the head of a high-level delegation of Syrian Cabinet ministers and military and intelligence officials on the eve of a state funeral for the 65-year-old premier.

Justice Minister Nabih Berri, leader of the Shiite Moslem Amal movement, blamed the Lebanese Forces -- the Christian militias -- for Karami's death and charged that they had "agents who have unfortunately infiltrated the ranks of the Army." Berri, in a televised interview, expressed doubts that a military investigation that has been ordered by President Amin Gemayel would have satisfactory results.

Berri specifically accused Lebanese Forces executive committee vice president Karim Pakradouni and Tewfic Hindi, an adviser to Christian militia commander Samir Geagea. Pakradouni and Hindi had publicly pressed Gemayel to accept Karami's resignation, which had been submitted May 4.

Hindi shrugged off the charges in an interview today, saying, "Everyone is accusing us as we appear to be the most likely candidates. But there are many here who want to take a stab at the Syrians."

Callers claimed responsibility for the assassination on behalf of two unknown organizations, but authorities said they were skeptical of the claims. Both accused Karami of involvement in attacks in Tripoli last December in which witnesses said at least 200 Sunni fundamentalists, their families and neighbors were massacred.

Berri urged that the investigation of the helicopter, which crash-landed after it was badly damaged by the explosion, take place outside Christian-controlled territory.