"It should be taken seriously because [Mehsud] has ordered the deaths of many Pakistanis and Afghans and has a close alliance with Al Qaeda," said James Phillips, a terrorism expert and senior research fellow for Middle Eastern Affairs at the Heritage Foundation.
"It's not too much of a stretch to think he might be involved in an attack on the U.S. if he's able to get his followers inside the United States. He's a militant extremist whose threats cannot be ignored."
Mehsud, 35, is the senior leader of Tehrik-e-Taliban, or the Taliban Movement of Pakistan, and is a key Al Qaeda facilitator in the tribal areas of South Waziristan in Pakistan, according to the U.S. State Department. A $5 million reward for information leading to his arrest and conviction was announced just last week.
"He has conducted cross-border attacks against U.S. forces in Afghanistan, and poses a clear threat to American persons and interests in the region," the State Department wrote in a March 25 release.
Phillips said Mehsud is less of a direct threat to the U.S. than bin Laden in an ideological sense, but his influence in Pakistan could allow him to tap into existing networks within Al Qaeda or among Afghan Taliban militants to achieve his goals.
"The U.S. government and other allied governments cannot afford to ignore this threat because [Mehsud] has acted on targets in the past," Phillips said. "Because he has a relatively secure base of operations in South Waziristan, he has been able to extend his influence throughout the border region and even into Pakistani cities."
Steve Emerson, executive director of The Investigative Project on Terrorism, said that of the many terrorists who have issued "blustery threats" in recent years, Meshud is considered a "rising young star" among militants.
"He's a dangerous guy," Emerson told FOXNews.com. "It just reaffirms the fact that Washington is a major target.
"He seems to be a pretty bloody, bold guy who is not afraid to have a marker on himself and knows how to exact publicity ... The real issue is what U.S. intelligence knows."
Malou Innocent, a foreign policy analyst at the Cato Institute, said Mehsud's attacks have "significantly altered" the political dynamics in Pakistan and provide a major test for President Asif Ali Zardari. But any direct threat Mehsud poses to the United States will be through his link with Al Qaeda, she said.
