FBI Director Robert Mueller, making the first ever visit by the agency's chief to Lebanon, visited on Thursday the site of the bombing where former Premier Rafik Hariri was killed, and met with officials as part of US efforts to help the government improve security after Syria's troop withdrawal early this year. While the US is not part of the UN investigation into Hariri's February 14 assassination, the FBI was involved in investigating at least three of a series of mysterious bombings against anti-Syrian figures since. The US Embassy and Lebanese security officials said Mueller met with Lebanese government officials, including Prime Minister Fuad Saniora and the police chief, Brig. Gen. Ashraf Rifi, during his three-hour stop in Lebanon. The FBI team later departed for Baghdad. The visit reflects growing US support for Lebanon as its relations with neighboring Syria, which the UN has implicated in the Hariri assassination. It also comes as America is waging a campaign of pressure against Syria, to force it to change its regional policies.