The use of homemade bombs extends well beyond Afghanistan and Iraq, making the weapons a global problem that requires an international solution, a senior U.S. military official said Thursday.

In congressional testimony, Army Lt. Gen. Thomas Metz said there have been more than 3,500 incidents around the world involving improvised explosive devices in the past year and the number is growing.

"Violent extremists will continue to wage conflict against human targets and the weapon of choice will continue to be the IED," he said at a hearing held by the House Armed Services oversight and investigations subcommittee.

The definition of an incident in this case includes IEDs that have exploded, failed to work, or were found and cleared.

Metz, who heads the Pentagon office tasked with countering IEDs, also said his organization is working to improve its operations and how it coordinates with the military services to ensure troops in the field have the best technology and training to counter the makeshift bombs.

In a new report, the Government Accountability Office said the office, formally known as the Joint IED Defeat Organization, is hampered by bureaucratic shortcomings that could lead to duplication of efforts or unneeded programs.

Metz said many of the problems cited by the GAO have already been addressed.

In Afghanistan, Metz said the number of successful IED attacks is growing as more U.S. forces are sent there.

According to the most current statistics from his office, there were 19 effective IED attacks in Afghanistan in September 2007; the attacks killed nine members of the coalition force and wounded 37 others. In September 2009, there were 106 effective attacks that killed 37 coalition service members and wounded 285 more.

The terrain and enemy in Afghanistan are very different from in Iraq, where the U.S. has been able to greatly reduce the number of IED incidents. Afghanistan's craggy landscape provides innumerable places to hide bombs, Metz said. And many Afghans are unwilling to turn in bomb makers and bomb layers because they've been intimidated by the insurgents and don't believe their government will help them.

But Metz cautioned that the focus should not be only on Afghanistan. IEDs are now a worldwide menace, with attacks occurring in the Philippines, Somalia, and Indonesia.

Two recent episodes demonstrate the threat of crude bombs "sits on our doorstep," he added. In September, the FBI arrested an Afghan immigrant and a Jordanian national for plotting to attack U.S. buildings with IEDs. Continued...