About 2,200 U.S. Marines arrived in Haiti on Monday, joining thousands more American forces  who are on the ground or just off shore to assist with the country's growing relief needs following last week's massive earthquake.  The troop deployments come as concerns over security grow and reports of looting and scuffles on the streets of Port-au-Prince continue.
Marine Major General Cornell Wilson says Monday's deployment boosts the total number of American forces in Haiti to more than 7,000.  U.S. commanders say more than 10,000 military personnel will be in the disaster zone in the coming weeks.

Wilson says the Marines arrived aboard the amphibious ship USS Bataan, and that the sea-based force will conduct a broad range of operations where access is challenged.

"The amphibious ships are loaded with helicopters, amphibious vehicles, trucks, generators and water purification units," said General Wilson. "The Marines and sailors will be supporting the interagency relief efforts led by USAID [the United States Agency for International Development]."

General Wilson says the Marines will stay as long as they are needed and will work with U.N. forces and the government of Haiti to handle security issues.

He says the U.S. military's key mission will be to provide water, food and medical care, but that it is prepared to help with evacuations or other operations.

"In the Marines mission, we are delivering humanitarian supplies," he said. "However, if that mission does come up [evacuations] and the JTF [joint task force] commander decides that is something we have to do, certainly we will comply with our orders."

In addition to the Marines, the Navy hospital ship USNS Comfort is expected to arrive in Haiti on Tuesday to help care for the thousands of wounded.

International aid agencies and U.S. officials agree that a military presence is needed in Haiti, especially given growing security concerns.

U.S. Defense Secretary Robert Gates says that maintaining security remains a high priority in Haiti.  But he has ruled out the United States taking on a broader policing mission.

Speaking onboard a flight to India on Monday, Gates said the thousands of U.S. troops that are being deployed to Haiti are there to support the United Nations and the Haitian government.

But he warned that there is a risk of violence erupting in Haiti.

"Until we can get ample supplies of food and water to people, there is a worry that in their desperation some will turn to violence," said Robert Gates.

Gates added that U.S. troops are authorized to use force to defend innocent Haitians and international relief workers, if necessary.