The approval, reached late on Thursday at the cabinet's weekly meeting, came despite objections from the minority ministers of the Hizb Allah group and its Shia Muslim ally, the Amal Movement, who warned against American interference now that the country is free of Syrian influence.
"We have knocked on the doors of all the countries that could help us," Prime Minister Fuad Siniora said.
"We are not facing an ordinary criminal... We are taking all measures in our hand. We will seek assistance to provide our forces with all the tools and programmes, equipment and also training so that we can live up to this challenge."
A team of FBI experts is in Beirut to help in the investigation of the latest bombing, which targeted prominent TV anchorwoman May Chidiac last Sunday. Chidiac lost her left leg and arm in the blast and is still in intensive care.
Siniora said that in addition to the United Nations, Lebanon approached Australia, Belgium, Britain, Canada, China, Egypt, France, Japan, Qatar, Saudi Arabia and the United States for security assistance. Britain, Egypt, France, Qatar, Russia and the United States agreed to provide training and equipment, he said.
European Union External Relations Commissioner Benita Ferrero-Waldner said on Friday in Beirut that the 25-member EU was fully ready to help Lebanon consolidate security.
"We do not trust America, nor trust its attitudes, promises, intelligence or projects"
Shaikh Naim Kassem,
"We will do what we can to help the Lebanese government re-establish security," Ferrero-Waldner said after holding talks with Lebanese Foreign Minister Fawzi Salloukh. "We are ready to support the Lebanese state if it has concrete requests."
Sunday's bombing was the 14th explosion in Lebanon in the past year. The most devastating blast came on 14 February, killing former Prime Minister Rafiq al-Hariri and 20 other people in Beirut.
The government has said it was helpless to identify who was behind the campaign that ensued. Siniora has warned of more violence as a UN investigation into al-Hariri's assassination that is targeting Syria and its Lebanese allies nears its end.
Beirut newspapers reported a heated, five-hour cabinet session on Thursday that was dominated by the issue of foreign assistance.
Hizb Allah and Amal ministers objected to the government's plan to seek foreign security assistance. "We expressed our viewpoint and our objection and we adhere to it," said Energy Minister Mohammed Fneish, a Hizb Allah member.
American involvement is a sensitive issue. It is opposed by Hizb Allah, which Washington brands as a terrorist group, and other pro-Syrian factions.
Hizb Allah's deputy leader, Shaikh Naim Kassem, has said the FBI agents were "suspicious and dangerous".
"We do not trust America, nor trust its attitudes, promises, intelligence or projects," Kassem said in a statement published on Friday. "We do not want America's intelligence or its investigation. America launched a war on Iraq with false intelligence information and this scandal was evident to the world."
Lebanon is still investigating the
death of Rafiq al-Hariri
Kassem said when the Americans intervene in Lebanon, "this means that the Israelis are present with their interests and policies".
Anti-Syrian groups have accused Syria and its Lebanese security allies of involvement in al-Hariri's killing, accusations that Damascus has repeatedly denied.
Al-Hariri's murder triggered mass protests and intensified international pressure that forced Syria to withdraw its troops from Lebanon in April, ending nearly a three-decade domination of its smaller neighbour.
Four pro-Syrian Lebanese generals have been arrested and accused of responsibility for al-Hariri's slaying, but there have been no arrests in the other bombings.