The man coordinating the response to the BP oil spill in the Gulf of Mexico said Sunday compared the disaster to an "insidious enemy."

Coast Guard Adm. Thad Allen, the national incident commander, said that trying to stop the oil leak has been a "frustrating" experience.

"I think everyone is anguished over this," he said on CNN's "State of the Union" program." You know, I have been working on the water for 39 years this is just completely distressing and it's very frustrating because this is spill has dissipated across southern Louisiana, to...Florida, it's like an insidious enemy that keeps attacking in different places. "

The government and BP have struggled to cap the leak, which has been flowing for about six weeks from a damaged pipe below the Deepwater Horizon oil rig.

President Barack Obama has called the spill the worst environmental disaster in U.S. history, and observers have called on the president and other officials to get tough with BP and show more emotion.

Obama last week said he was "furious" over the spill, but said that anger alone would not plug the leak. He also made his third visit to the Gulf coast on Friday, meeting with local residents who have been affected by the oil washing ashore.

Allen -- the president's point man on the spill -- said it was important to stay focused on stopping the leak coming from a mile below sea level.

"It's going to be there for a while and we have to redouble our efforts, we have to be right on the game, and we have to support the local folks there," he said. "We have to stay on it."