U.S. counterterrorism officials remain concerned about al-Qaida in Iraq, even though terrorist leader Abu Musab al-Zarqawi was killed in a U.S. airstrike last week. The officials testified about the al-Qaida threat at a Senate hearing.

As the Senate Foreign Relations Committee conducted its hearing on the threat posed by al-Qaida in the aftermath of Zarqawi's death, the full Senate passed a resolution commending U.S. troops for their actions that led to the terrorist's demise.

Bill Frist, right, with Defense Secretary Donald H. Rumsfeld, addresses media on Capitol Hill, Tuesday, June 13, 2006 after a briefing on war in Iraq

Majority Leader Bill Frist, a Tennessee Republican, sponsored the measure.

"This is a severe blow to al-Qaida and the terrorist enemy in Iraq," he said. "It marks yet another victory in the global war on terror."

But counterterrorism officials testifying before the Senate Foreign Relations Committee offered a much more sober assessment.

The Director of the National Counterterrorism Center, former Navy Vice Admiral John Scott Redd says al-Qaida and its core leadership are still a preeminent concern, saying they are resilient, smart and committed to their cause.

John Scott Redd

Redd expressed concern about al-Qaida's central organization joining ranks with its off-shoot in Iraq.

"We also worry about the merger between al-Qaida and al-Qaida in Iraq, or AQI, the group formerly headed by Abu Musab al-Zarqawi," he said. "Eliminating Zarqawi is clearly a major step forward, but both al-Qaida and AQI will continue with their deadly work."

Henry Crumpton, coordinator for counterterrorism at the State Department, echoed the comments, saying although Zarqawi is dead, al-Qaida in Iraq still poses a threat not only for Iraq, but for the region.

Admiral Redd says officials also are concerned about other Sunni Muslim terrorist groups that are inspired by al-Qaida.

"Although they tend to be regional in nature, many of these groups increasingly see themselves as part of a global, valid extremist network and may indeed target United States' interests overseas," he said.

In addition, Redd said intelligence agencies are worried about homegrown terrorists, like the 17 people arrested in Canada earlier this month who are suspected of plotting attacks. He said while such terrorists are not controlled by al-Qaida, they draw inspiration from the group's ideology.

Redd was asked what impact the death or capture of al-Qaida's leader, Osama bin Laden, would have on the organization. He said it would be mostly symbolic, and would not have a major impact on the network's operations.