Beirut, Lebanon ? The United Nations named four pro-Syrian generals and a former legislator as suspects Tuesday in the February assassination of former Prime Minister Rafik Hariri – the first break in a crime that transformed Lebanon.

U.N. investigators were interrogating the men at a hilltop hotel overlooking Beirut after searching the generals’ homes. The Lebanese government, acting at the request of the U.N., detained three of the suspects; a fourth surrendered for questioning and a fifth returned from Syria, promising to cooperate.

Tuesday’s startling developments could produce serious political fallout in the country, particularly by targeting the commander of the Presidential Guards Brigade, Brig. Gen. Mustafa Hamdan, who provides security for and is an associate of pro-Syrian President Emile Lahoud, a bitter political foe of Hariri. Hamdan voluntarily appeared for questioning.

Divers from the U.N. investigators' team and Lebanese civil defense carry a chunk of debris Saturday for possible use as evidence in the Feb.14 explosion that killed former Lebanese Prime Minister Rafik Hariri near the Saint Georges Hotel's bay in Beirut, Lebanon.

Lahoud said the summonses were not arrests and praised Hamdan as “one of the best officers in the Lebanese army.”

Besides Hamdan, the generals swept up in Tuesday’s actions were: Maj. Gen. Jamil Sayyed, former chief of the powerful General Security department; Maj. Gen. Ali Hajj, former police chief; and Brig. Gen. Raymond Azar, former head of military intelligence.

The four generals already have been questioned by German prosecutor Detlev Mehlis, the U.N. chief investigator who requested that the men be summoned.

Details of the investigation are secret and nothing was known about what evidence led to the detentions. All of those being interrogated were still in custody late Tuesday and could not be reached for comment.

Three other officers and Hamdan’s brother also were detained for questioning, state television reported.