KABUL, Afghanistan - The number of roadside bombs and kidnappings doubled in Afghanistan in 2008 from the year previous, the U.S. ambassador said yesterday, grim statistics that underscore the country's deteriorating security situation.

The number of roadside bombs rose from roughly 1,000 in 2007 to 2,000 in 2008, while the number of kidnappings jumped from about 150 to 300, Ambassador William Wood said. Compiling accurate data for roadside bombs and kidnappings is difficult, he said, and the numbers are approximate.

Speaking at an end-of-the-year news conference, Wood called 2008 a "good year, but also a hard year."

Afghanistan, he said, saw progress against opium poppies, the main ingredient in heroin, as land for cultivation dropped by almost 20 percent in 2008. International donors also pledged $20 billion in aid at a conference in Paris.

But violence rose and the Taliban insurgency spread throughout southern Afghanistan. Because of that, the United States next year will send up to 30,000 new forces to the country to reinforce the 32,000 American troops there.

The rise in the number of improvised explosive devices, or IEDs, likely came because Taliban and other fighters cannot compete with U.S. and NATO forces on the battlefield, Wood said.

The Taliban in the last year has pushed into remote areas of Afghanistan where the government has little presence and Afghan and international security forces rarely reach. To counter that, the United States will soon begin a pilot program to train Afghan tribal members selected by their local leaders to help defend their villages.

Wood stressed repeatedly that the United States would not provide any weapons for the community defense program and that it was not the re-creation of tribal militias. He said that Afghans had always depended on local groups to defend their communities and that President Hamid Karzai asked the United States to strengthen villagers' defense initiatives.

Community-selected tribesmen would receive training, uniforms, and means to communicate with Afghan and international security forces in case of an attack, Wood said.