Lt. Gen. Jeffrey S. Buchanan, commander of U.S. Army North (5th Army) at Joint Base San Antonio-Fort Sam Houston, in June. (Staff Sgt. Tomora Nance/U.S. Army North Public Affairs)

The U.S. military will introduce a new senior commander in Puerto Rico, a three-star officer who will coordinate military relief efforts following Hurricane Maria but not command a full joint task force that has been formed after similar operations in the past.

Lt. Gen. Jeffrey S. Buchanan, the commander of U.S. Army North, will “serve as the Department of Defense’s primary liaison” to FEMA as the Pentagon shifts from running relief operations primarily from the sea to mostly ashore, U.S. Northern Command said Thursday in a statement. Buchanan’s deployment comes in addition to that of Army Brig. Gen. Richard Kim, who arrived in Puerto Rico on Wednesday and is Buchanan’s deputy commander at U.S. Army North.

The U.S. military has often deployed three-star commander to oversee relief operations, including after Hurricane Katrina in 2005, the earthquake that devastated Haiti in 2010 and the typhoon that struck the Philippines in 2013. But Buchanan’s deployment in this case comes eight days after the storm charged across Puerto Rico with Category 4 strength and long after the Pentagon has tapped officers for similar operations in the past.

Buchanan will arrive in Puerto Rico as the Trump administration continues to take criticism for its response to the hurricane. Most of the island of 3.5 million people still does not have power, and about half of the island is without safe drinking water. U.S. officials have said major priorities in coming days include clearing roads of debris and distributing supplies.

U.S. officials have defended their response to the storm, saying the destruction it caused made it extremely difficult to have a true sense for how serious the situation was. The Pentagon has begun accelerating its response this week, opening a second airfield at the former Naval Station Roosevelt Roads, preparing the hospital ship USNS Comfort to deploy from Norfolk and establishing a caravan of cargo jets filled with equipment and supplies.

Kim, speaking in a conference call to reporters, said Thursday that there are about 4,400 U.S. troops involved in the operation, counting all active-duty personnel and National Guardsmen on the island and U.S. service members supporting the mission by flying in supplies or serving on the two Navy ships off the coast.

A Pentagon spokesman, Lt. Col. Jamie Davis, has previously said the number is about 5,000. The National Guard has a combined 3,000 on duty responding in Puerto and the U.S. Virgin Islands, it said Thursday on Twitter.

Deputy Defense Secretary Patrick Shanahan spoke Thursday from the Pentagon with Puerto Rico Gov. Ricardo Rosselló, underscoring that supporting the U.S. territory is a major priority and the Defense Department will deploy all resources needed to do so, the Pentagon said in a statement.

“The leaders discussed the rapid deployment of additional response capacity, expanding airfield throughput, and positioning key DOD leaders in Puerto Rico,” the statement said, using an acronym for Department of Defense. “DOD also continues to support FEMA’s immediate objectives to complete hospital assessments and establish an island-wide commodities distribution plan.”

Buchanan is an infantry officer who has deployed four times to Iraq and once to Afghanistan. Before to taking command of U.S. Army North, he was deputy commander for operations for U.S. forces in Afghanistan for about a year stretching between 2015 and 2016.