Defense Secretary Jim Mattis said Tuesday that about 10,000 troops were on the ground in Puerto Rico and there was no delay in the Pentagon meeting requests for aid, despite criticisms that the administration has been slow to deploy forces to the island.

"I assure you this is all hands on deck. There is no delay, when a request comes in it is approved the moment it hits the Pentagon," Mattis told the Senate Armed Services Committee during testimony.

President Trump, who was visiting Puerto Rico Tuesday, touted the low number of deaths so far reported in the disaster. He has been pushing back against criticism in the past week over his administration's effort to aid Puerto Rico and its 3.4 million U.S. citizens after the island was hit this month by Hurricane Maria.

Critics, for the most part, have stopped short of faulting the military. Rather they have said the White House has been slow to request the forces, which the Pentagon, in turn, responds to quickly.

Sen. Richard Blumenthal, D-Conn., said he recently met with Defense Department and Federal Emergency Management Agency officials and found the military was still not doing enough, a refrain from Democrats on Capitol Hill.

"What impressed me is, very bluntly, was the need for additional troops and resources there from the Department of Defense in order to fill the gap and the disconnect between the supplies that are in the ports and airports and the people," said Blumenthal, who is a committee member.

Mattis told Blumenthal that the department has pulled out all the stops to help U.S. citizens on the island.

"There is no lack of resources, sir, we are ready to go even to the point that it is going to impact the deployments perhaps of some of these troops overseas next year because we have interrupted the preparation. That is OK, when it is helping fellow Americans," he said.

Also on Tuesday, Rep. Adam Smith, D-Wash., said Puerto Rico continues to suffer from a lack of military resources.

"The military effort in Puerto Rico and the Virgin Islands continues to be significantly under-resourced and we are still not responding properly to the logistical needs at hand," said Smith, ranking member of the House Armed Services Committee. "These U.S. citizens are in desperate need of heliborne airlift and search capability, truck drivers, and civil engineers to clear roads and enable the delivery of food, water, and supplies.

"There are only some 10,000 troops involved, in contrast to 60,000 during Hurricane Katrina and 22,000 during last year's Haiti earthquake," he continued. "The USNS Comfort is only just arriving and President Trump just now visiting the site of a hurricane that happened on September 20. The USS New York and USS Iwo Jima, which helped with relief in Florida during Hurricane Irma, are still sitting in dock in Florida."