Oklahoma's senior U.S. senator said the counterterrorism program created following the Sept. 11, 2001, terror attacks has foiled dozens of terrorist plots in the U.S. but that more work needs to be done to detect and prevent future plots.

Republican Sen. Jim Inhofe, a member of the Senate Armed Services Committee, discussed the nation's counterterrorism efforts and current terrorist threats to the U.S. during a luncheon speech at the Oklahoma City Bombing Memorial & Museum.

Inhofe said the terrorist attack 16 years ago that remains the deadliest domestic attack in U.S. history gives Oklahomans a different perspective on the impact of violence than other parts of the nation that have not experienced terrorism.

"We were the first. When it happened here, we knew how to respond," Inhofe said.

Inhofe said more than 40 terrorist plots have been prevented since the Sept. 11 attacks, thanks to counterterrorism agencies created afterward like the Department of Homeland Security and the National Counterterrorism Center as well as the Patriot Act, which expanded law enforcement's ability to investigate individual's suspected of terrorist-related activities.

The foiled plots include the planned attack on Fort Dix, N.J., by a tiny cell of homegrown terrorists in 2007 and the 2002 plot to detonate a radioactive "dirty bomb" in the U.S.

In spite of the nation's successes, Inhofe says more needs to be done to detect and prevent future attacks including rebuilding the nation's military and strengthening partnerships with friendly nations.

Inhofe said anti-terrorist successes in the Middle East have pushed some terrorist cells and activities into Africa, raising fears that the continent could become another safe haven for terrorists as Afghanistan was for Al Qaeda prior to the Sept. 11 attacks.

"Africa is another area we have to watch," said Inhofe, who said he has made 116 visits to African nations in the past 15 years. He said the U.S. has helped train and equip five brigades of African troops to help stamp out terrorist activity.

Inhofe said he is also concerned about the nuclear threat posed by Iran, which he said will have the ability to threaten Western Europe and the eastern U.S. by 2015.