PORTLAND – As President Bush defended the American mission in Iraq amid mounting casualties, U.S. Sen. Susan Collins, R-Maine, said Sunday she believes more troops are needed in that country.

Appearing on ABC’s “This Week,” Collins was asked whether she believes more troops are needed for the short term in Iraq.

“I do,” said Collins, a member of the Senate Armed Services Committee. “But the answer is not to extend the stays of the very weary reservists and National Guardsmen who have already been there for a year.

“The answer is to redeploy American troops from other areas,” said Collins, who also said the current instability in Iraq is disturbing. The senator added that she has concerns about the planned transfer of power to the Iraqis in June.

A day earlier, Collins said she was troubled by word that an Army Reserve unit with a Saco-based platoon would not be coming home from Iraq on Easter Sunday as previously planned.

After being moved from Iraq to Kuwait two weeks ago, the 94th Military Police Company has been “put on hold indefinitely” while awaiting further orders, said Jennifer Stegeman of Dayton, wife of a member of the 94th.

Collins announced the delay in the return of the unit, which has headquarters in Londonderry, N.H., after talking with some of the wives of the Saco platoon.

“It is troubling that these Maine soldiers, who are deeply missed by their loved ones, will not be coming home as expected,” Collins said in a statement.

“While little is known about the circumstances surrounding the delay of their return home, I have contacted the Pentagon to express my deep concerns. I will continue to pursue more information about this matter,” Collins said.

Later Sunday, Collins issued a statement that quoted a Pentagon official as saying all troops scheduled for rotation out of the region have been frozen in place pending a unit evaluation.

Jennifer Stegeman said she received a call Saturday from her husband, Sgt. 1st Class Rick Stegeman, who outlined three possible scenarios for the unit’s 150-plus soldiers: a return to Iraq, a return home or a continued stay in Kuwait.

She said uncertainty about when the soldiers will come home has left family members emotionally drained and they can only guess what will happen next.

Nancy Durst, wife of Staff Sgt. Scott Durst from southern Maine, said it was unfair to ask more of the part-time soldiers.

“These guys are exhausted,” she said. “They shouldn’t send beaten-up soldiers back into combat. I don’t know what this administration’s thinking.”

On Sunday, Bush braced the country for the possibility of more American casualties in Iraq while saying the U.S.-led mission is just.

“Obviously every day I pray there is less casualty, but I know what we are doing in Iraq is right,” Bush said in Fort Hood, Texas, after attending an Easter service.

The 94th was deployed in December 2002 but didn’t arrive in Iraq until the next April. A combat MP unit, the company is trained to keep supply lines secure and other military units safe.

The unit originally was scheduled to come home last fall, one year after its deployment. But under a new Army policy, reservists and National Guard units can spend 12 months in the country to which they are deployed.

The company spent nine months on a peacekeeping mission in Bosnia before being sent to the Middle East.