U.S. Ambassador to Iraq L. Paul Bremer (search) and lawmakers said Sunday the Iraq coalition needs better intelligence, more resources and more cooperation from the Iraqi people to stabilize the volatile situation there. 

But there were differing opinions about the best way to make that happen.

"We have three levels of security problems here," Bremer said on "Fox News Sunday (search)." "One is ... terrorists appear to be reinfiltrating into Iraq. ... What we need is better intelligence against them, and we're going to try to do that."

The other two security threats are those against coalition forces and the Iraqi infrastructure, he told Fox News. But Bremer maintained that more troops weren't necessary.

"It's not a question of more troops, it's a question of being effective with our intelligence, getting more Iraqis to help us," Bremer said on ABC's "This Week."

About 150,000 U.S. troops are in Iraq now, along with 20,000 international troops who are part of the U.S.-led coalition.

As investigators search for clues over who was responsible for this week's bombing of the U.N. headquarters in Baghdad, there is growing fear among Americans that the U.S. could be bogged down for years in what could be a hopeless situation.

Lawmakers who recently visited Iraq weren't so pessimistic, but believe the U.S. needs to direct more resources and military personnel toward Iraq.

The former ambassador to Morocco, Fox News contributor Mark Ginsberg (search), said more ground troops from various countries were exactly what is required to bring the situation in Iraq under control. 

But he said the U.S. can't do it all alone.

"We have infrastructure problems ... We have border problems. We're doing a miserable job sealing the borders," Ginsberg told Fox. "If we put more troops on ground ... more Jordanians on the Jordanian border, more Turkish troops on the Syrian border — that's what we need right now. We need a resolution that allocates that responsibility.

"What we want to do is get it right," Ginsberg added. "We're not able to get it right unilaterally. We're going to be able to do it multilaterally."

Sen. Joseph Biden (search), D-Del., said the Bush adminstration was sending mixed messages and acting indecisive about how to remedy the Iraq situation.

"We have to act more decisely in Iraq by getting the international community involved and providing resources," he said Sunday. "You have the administration saying, we don't need the U.N. At the same time, others are saying, we need more forces and other nations are saying, we need a U.N. resolution to give us cover. I don't understand why this is so difficult."

Bremer said the United States would welcome more help from other countries, but he stopped short of saying the military would cede some control to the United Nations (search) — as France, India and other nations have insisted.

Gen. John Abizaid, commander of U.S. forces in Iraq hasn't requested more soldiers, though the Pentagon would approve them if he did, Gen. Richard Myers (search), chairman of the Joint Chiefs of Staff, said during a round of Sunday television news shows.

"We are stretched thin, but we have more troops to send," Myers said on NBC's "Meet the Press."

But some critics have said inserting more troops into Iraq could further weaken U.S. military strength. The United States also has long-term commitments in Kosovo and Afghanistan, among other places, and recently deployed a small peacekeeping force to Liberia.

Some lawmakers said more funds are needed to boost the instability in Iraq.

"Theinfrastructure needs in Afghanistan and Iraq are in the billions," said Sen. Lindsey Graham, R-S.C., on "Fox News Sunday." "We are underestimating the cost of the conflict, and we in the House and Senate need to appropriate a lot more money."

Congressman Harold Ford Jr. agreed, but said the money shouldn't be coming from the U.S. alone.

"We cannot rebuild the water and energy - or should I say electricity - infrastructure ourslves," said Rep. Harold Ford Jr., D-Tenn. "We're talking $30 billion over the next four years."

Ford said those costs, coupled with the funds needed to address the security concerns in Iraq, are too much for the United States to handle on its own, especially in the current domestic economic climate.

Fox News' Sunday host Tony Snow, Catherine Donaldson-Evans and The Associated Press contributed to this report.