UNITED NATIONS - The United States has quietly dropped plans to seek an international investigation into the killing of a prominent anti-Syria journalist and will leave the probe to Lebanon, U.N. diplomats said on Tuesday.

Washington had announced last Friday that it wanted the U.N. Security Council to expand an existing independent inquiry into the assassination of former Lebanese Prime Minister Rafik al-Hariri to include the murder of columnist Samir Kassir.

But it reversed course after Beirut signaled it would conduct an aggressive probe of Kassir's death and invited FBI agents and French police to help, the diplomats said.

Expanding the Hariri inquiry would have required U.N. Security Council approval in the form of a resolution. "This was an idea, but they didn't push it," said French Ambassador Jean-Marc de la Sabliere, the council president for June.

Instead of a resolution, the council on Tuesday unanimously approved a statement drafted by Washington that welcomed the Lebanese government's "determination and commitment" to bring to justice those responsible for Kassir's killing.

The assassination "constitutes a pernicious effort to undermine security, stability, sovereignty, political independence and efforts aimed at preserving civil accord in the country," the statement said.

"The sponsors of recent terrorist acts against political leaders and leading members of civil society in Lebanon should not be permitted to jeopardize the holding of parliamentary elections in transparent, free and democratic conditions," the statement said, referring to voting going on until June 19.

Kassir, 45, was killed June 2 when a bomb exploded in his car in Beirut four days after the start of elections, conducted region by region over four weekends. The bombing shocked a country still coming to terms with Hariri's killing in February.

Kassir worked for Lebanon's leading An-Nahar daily and had for years urged an end to Syria's role in Lebanon. Opposition figures were quick to accuse Damascus and its allies for his death. Syria has rejected the accusations.

Syria ended its 29-year military presence in Lebanon in April under international and Lebanese popular pressure. (Reuters)