The top commander of U.S. forces in South Korea says he is concerned about North Korea's growing capability to carry out attacks through nonconventional means, such as cyber warfare and chemical weapons.

Speaking to the House Armed Services Committee on Wednesday, General James Thurman said North Korea's advances in computer hacking and biological weapons, combined with its massive conventional military, pose a serious threat to South Korea.

“North Korea continues to pursue asymmetric capabilities, especially in the areas of nuclear, missile and cyber. The development of these asymmetric capabilities and the forward stationing of its conventional forces provide North Korea the ability to attack or provoke the Republic of Korea with little warning.”

Thurman also warns that, if left “unchecked,” the development of Pyongyang's missile capability could eventually threaten the United States.

But he says that the nearly 30,000 U.S. troops stationed in South Korea are well positioned to repel any potential attack from North Korea, which has the fourth largest army in the world.

The hearing comes amid a dispute with North Korea about its recently announced plans to launch a weather satellite into orbit. The U.S. and its allies say the launch is an excuse for Pyongyang to test long-range ballistic missiles, an activity banned under United Nations sanctions.

Appearing at the hearing, Peter Lavoy, the acting assistant secretary of defense for Asia-Pacific security, said the debris from such a launch could cause casualties in North Korea's neighboring countries.

“The North Koreans have indicated that they will launch the missile in a southward direction. And, I don't know if we have any confidence on the stability of the missile or where the actual impact will be. A number of countries are potentially affected. This could fall on — the debris could fall on their countries; could cause casualties. This — this affects South Korea, of course, but also Japan — Okinawa, the island of Japan.”

North Korea announced plans for the mid-April launch just weeks after agreeing to freeze its nuclear activities and missile tests. In return, the U.S. agreed to send 240,000 tons of food aid to the impoverished country.

On Wednesday, Lavoy announced a suspension of the food aid, saying North Korea had failed to live up to its international obligations. He also said Washington is not convinced the food aid would reach those most in need.

North Korea has vowed to continue with the satellite launch, saying it is for peaceful scientific purposes and meant to celebrate the 100th birthday of its founding leader, Kim Il Sung.