South Korea/Japan: S. Korean president heads to Japan for summit talks.

Section: General News - South Korean President Lee Myung-bak left for Japan on Sunday for talks with Japanese Prime Minister Taro Aso on ways to increase security cooperation between their countries amid escalating tension over North Korea's continued drive to develop nuclear weapons and ballistic missiles.

Pyongyang is likely to top the agenda at the summit meeting, as it follows the North's nuclear test last month and threats to make more nuclear weapons.

South Korea and Japan are members of six-nation talks aimed at denuclearizing North Korea, a forum that also involves the U.S., China and Russia.

Pyongyang withdrew from the talks in protest at the U.N. …