Debris from the bomb explosion that damaged the Cuban diplomatic mission here late Friday was taken yesterday to the FBI laboratory for examination but officials said they had not identified any suspects in the blast.

The FBI said it was investigating a telephone call made more than an hour after the explosion in which a man described as having a slight Spanish accent attributed the blast to Omega 7, an anti-Castro Cuban group that has been linked to other bombings in the United States in the past.

An FBI spokesman said yesterday the bomb was apparently thrown over a fence at the rear of the Cuban mission at 2630 16th St. NW. Windows in the building and in surrounding structures were reported broken. No injuries have been reported.

According to the FBI, a small crater was found in a stairwell at the bottom of a flight of steps leading to a rear door of the mission, now known as the Cuban Interests Section.

The elegant sandstone building housed the Cuban Embassy here before the rupture of diplomatic relations in 1961 between the United States and the Castro government. The Cuban Interests Section was opened in the building on Sept. 1, 1977.

The State Department conveyed its regret to the Cubans yesterday over what it described as a "very unfortunate incident."

The Department said that it would insure that the blast is investigated thoroughly and that it would "make every effort to see that the parties responsible were brought to justice," according to a department spokeswoman.

Initial reports Friday night indicated that two men were seen running from the area of the mission about the time the bomb went off. Authorities indicated no progress yesterday in confirming the reports.

The principal responsibility for protecting foreign diplomatic premises here is held by the uniformed division of the Secret Service. One source familiar with security in the area of the Cuban mission said Secret Service patrol strength there has recently been reduced by budgetary restrictions.