Story highlights The extended missile range allows Seoul to defend itself, a security official says

The agreement allows Seoul to fire missiles up to 800 kilometers (497 miles)

At that range, South Korean missiles could strike the northern peninsula of North Korea

Previously, the South agreed to limit its missile range in exchange for access to U.S. technology

South Korea announced Sunday that it reached a deal with the United States that allows Seoul to extend the range of its ballistic missiles, a move a senior security official says will deter military provocation from North Korea.

The announcement from South Korean national security adviser Chun Yung-woo comes amid increased tensions between the two Koreas following Pyongyang's test firing in April of a long-range rocket, which exploded shortly after it was launched.

The deal with Washington revised the range of Seoul's missiles from 300 kilometers (186 miles) to 800 kilometers (497 miles), Chun told reporters.

"The important goal in revising the missile pact is to deter armed provocation from North Korea," Chun said.

"If North Korea is to attack or provoke, we are able to incapacitate its nuclear and missile (capabilities) in the early stage. We have guaranteed various capabilities to protect the life and safety of our people."

At that range, the missile range would include North Korea's northern peninsula.

Under the amended pact, South Korea also can increase its current restricted payload of 500 kilograms (1,100 pounds), depending on the range of the missile. The plan allows for three times the current payload for ballistic missiles with a range of 300 kilometers.

South Korea first agreed in 1972 to limit its missile range to 180 kilometers (112 miles) in exchange for access to U.S. missile technology. A bilateral agreement between the two countries was signed in 1979, though the guidelines were revised in 2001 to allow for a range of 300 kilometers.

The two Koreas signed an armistice that ended the 1950-1953 Korean war, though a peace treaty was never signed. Technically, the two countries remain in a state of war.

Roughly 28,000 U.S. troops are stationed in South Korea.