American diplomats and other mission employees may not be safe in Iraq if the U.S. military leaves the volatile country at the end of the year as planned, according to a new report released Tuesday.

The report by the U.S. Senate Foreign Relations Committee puts new pressure on a delicate diplomacy between Washington and Baghdad to decide what future role American troops will have in Iraq -- if one at all -- before they start withdrawing this summer.

At least 159 Iraqi citizens and 100 police and soldiers were killed in insurgent attacks in January -- the deadliest month for Iraq since September, according to data released Tuesday by security and health ministry officials in Baghdad.

An Associated Press count of Iraqis killed in attacks over two weeks alone puts the death roll at more than 200.

"The situation in Iraq is at a critical juncture," concluded the report, issued a few hours before Ambassador to Iraq James F. Jeffrey and Army Gen. Lloyd Austin, commander of the U.S. military in Iraq, appear before the Democrat-led Senate panel.

"Terrorist and insurgent groups are less active but still adept, the Iraqi army continues to develop but is not yet capable of deterring regional actors, and strong ethnic tensions remain along Iraq's disputed internal boundaries," the report said. "Although a government has finally been formed, it remains to be seen how cohesive and stable it will be."

The report mostly focuses on protecting the U.S. Embassy in Baghdad and its four satellite offices around Iraq after the planned Dec. 31 withdrawal, a deadline required under a security agreement between the two counties.

It also looks at a compromise plan between a full military withdrawal and keeping combat forces in Iraq, which Prime Minister Nouri al-Maliki has signaled he will not permit.

Such a compromise could assign a robust military staff to the Embassy's security office that officials in Baghdad and Washington have said could house as many as between 100 and 800 soldiers. But that plan also has drawbacks, the report said, noting that "though such a force would have little interaction with the Iraqi public, it might also be cited as evidence that the United States has no intention of leaving Iraq."

In an unrelated interview this week, U.S. Lt. Gen. Robert Cone, a deputy force commander in Iraq, said he is unaware of any plans for the military to stay beyond 2011. "It is our policy to withdraw by December 2011," he said.

Noting the current unrest in Egypt, he added: "You could look at Iraq among other counties in the region right now as relatively stable."

Violence is down from the widespread tit-for-tat sectarian killings that brought Iraq to the edge of civil war just a few years ago. But deadly bombings and shootings in Iraq still occur on a near-daily basis.

An almost daily barrage of bombings in January lasting almost two weeks -- mostly targeting Shiite pilgrims and security forces -- made it the bloodiest month in Iraq since September.

The Senate report suggests that U.S. military and Iraqi leaders alike want Americans combat troops to remain beyond 2011, but acknowledges political pressures in both nations that would make that hard, if not impossible.

But the report concluded that too many lives have been lost -- more than 4,400 soldiers alone -- and more than $750 billion spent to abandon U.S. hopes of forging a long-term diplomatic relationship with Iraq.

"Some will argue that the war's faulty pretext -- that Iraq's supposed weapons of mass destruction stocks constituted a grave and gathering danger -- justify a quick American disengagement from Iraq once our troops are withdrawn next year," the report said. "While such an approach may be ideologically fulfilling, it constitutes snatching defeat from the jaws of victory.