Three men identified as members of the staff of the president of Tunisia were removed from a Paris-bound flight waiting to take off from Dulles International Airport last night after one of them told a flight attendant that he had a bomb in his bag, airport police said.

TWA flight 890 was delayed about two hours after the 6:40 p.m. incident while crews hand-searched baggage belonging to the three men, police said. No bomb was found.

In another, apparently unrelated incident at National Airport yesterday, a Falls Church cabdriver who attempted to board a Ransome Airlines flight to New York, where he was to connect to a flight to Beirut, was detained after his checked luggage was found to contain guns and ammunition.

Airport police officer J.D. Allen said the three men removed from the Paris-bound flight at Dulles claimed diplomatic immunity in the incident and none was charged. Joking about having a bomb aboard an aircraft is a federal crime.

After being questioned nearly three hours, the three were escorted away by an embassy official, Allen said.

He said a flight attendant aboard the plane had told one of the men in the Tunisian party that he would have to stow a cumbersome bag he was carrying, and at that point the man remarked that the bag contained a bomb.

When taken into custody by police, Allen said, the three men claimed diplomatic immunity. He said one of them was identified as a security officer for Tunisian president Habib Bourguiba and that the other two were members of the president's staff.

According to Allen, the embassy of Tunisia dispatched to the airport a man he identified as second secretary Hatem Atallah, who helped interview the three men about the incident.

Allen said the man who spoke to the flight attendant on the plane explained in the interview that his comment "was made as a joke."

"The secretary [Atallah] related his personal apology on behalf of the president of Tunisia," Allen said.

In the National Airport incident, Federal Aviation Administration spokesman Dennis Feldman said last night that a 37-year-old man, was arrested about 1:30 p.m. after security checks disclosed that his luggage contained a 12-gauge shotgun, an air rifle, 150 rounds of .45-caliber ammunition and a box of pellets. Feldman said it is illegal to transport firearms in checked luggage without declaring them.

The man was being held last night at the Fairfax County Detention Center.