North Korea threatened "physical response" to U.S. and South Korean military drills to be held July 25-28, a North Korean spokesman said on Friday.

"There will be physical response against the steps imposed by the United States militarily," Ri Tong Il said at the Association of Southeast Asian Nations (ASEAN) meeting in Hanoi, Vietnam, adding that the exercise will be "another expression of hostile policy" against North Korea.

"It is no longer the 19th century. The present century is one of peace and stability," Ri said.

Joint U.S.-South Korean military drills are due to be held in the Sea of Japan starting this weekend. Initially, the exercises were scheduled on June 8-11, however, they were postponed as the sides decided to wait for a UN resolution on the sinking of South Korea's Cheonan corvette.

The 1,200-ton South Korean warship sank near the disputed Northern Limit Line in the Yellow Sea on March 26, causing the loss of 46 lives. South Korea says it has proof that North Korea fired a torpedo at the vessel from a submarine, although Pyongyang denies the attack.

The UN Security Council condemned the incident and stressed the need to prevent similar attacks in the region, but did not place the direct responsibility on North Korea.

Ri said the joint military drills threatened North Korean sovereignty and security on the Korean Peninsula and Asia as a whole.