North Korea's refusal to discuss alleged violations of the armistice that ended the 1950-53 Korean War raises serious security concerns, the U.S. military commander in South Korea said.

In a statement released Sunday, Gen. Leon J. LaPorte said the North Korean military had not recognized terms of the armistice, which governs conduct in the Demilitarized Zone separating communist North Korea from South Korea.

The U.S.-led U.N. command said they presented North Korean officers with photographs of their troops with light machine guns in the DMZ last month. The armistice allows only small arms and rifles into the zone.

According to the U.N. command, the North Koreans said the matter was outside the authority of the armistice. South Korean soldiers saw the North Korean machine guns in an area where both sides are building a cross-border railway.

"This raises serious security concerns in the transportation corridors" and sets a "dangerous precedent," LaPorte said.

He said that if the North Koreans continue to ignore armistice regulations, "it could undermine the armistice's most significant visible mechanism for maintaining a separation of opposing forces — the DMZ."

The Korean War ended without a peace treaty, and the buffer zone, or DMZ, has been the site of numerous confrontations in past decades, though such incidents have become rare in recent years.

"If this situation continues, I believe the (South) Korean peoples' security could be diminished by North Korea's continued refusal to discuss their most recent armistice violations," LaPorte said.