WASHINGTON (Reuters) -- The White House on Friday accused Syria of interference and intimidation inside Lebanon during national elections and demanded that it remove intelligence agents.

Lebanon's elections, the first in three decades without a Syrian military presence, are being held in different regions over four weeks from May 29 to June 19.

The United States had demanded for weeks before the elections began that Syria must withdraw all intelligence agents. Syria has said it had removed all military and intelligence operatives, but White House spokesman Scott McClellan said the international community must tell Damascus to "stop meddling."

"We are deeply concerned about Syria's interference and intimidation inside Lebanon. Syria needs to comply fully with United Nations Security Council resolution 1559. That means getting all their intelligence operatives out of Lebanon," McClellan said.

He spoke a day after U.S. Secretary of State Condoleezza Rice expressed concern about the possibility of a "pattern" of political killings in Lebanon.

Former Lebanese Prime Minister Rafik Hariri was assassinated in February and anti-Syrian columnist Samir Kassir was killed last week in Beirut.

Bush administration officials say the United States has received "credible" word that Syria has developed a "hit list" targeting prominent Lebanese political leaders, The New York Times and The Washington Post reported.

Both newspapers cited a senior administration official as saying Syria's plan was aimed at creating instability in an attempt to regain control of Lebanon.

McClellan, asked about the report of a hit list, said he could not comment on intelligence matters.

He said the United States wanted to see Lebanon's elections proceed "in a free and fair manner without any outside interference or intimidation."

"We are concerned that those intelligence operatives are interfering with Lebanon's internal affairs. That concern is real," McClellan said.

He repeated a call for the United Nations to send verification teams back to Lebanon and said Secretary-General Kofi Annan was looking at that possibility.

"It's important for the international community to send a clear message to Syria that it must stop meddling in Lebanon. I think the world is watching Lebanon closely," he said.