U.S. Secretary of Defense Ash Carter and South Korean counterpart Han Min-koo urged North Korea to stop all activities related to its nuclear programme. Speaking at a news conference in Seoul, Carter said both the heavily fortified border and the 2010 attack against a South Korean navy ship were evidence of the North's persistent threat. (SOUNDBITE) (English) U.S. SECRETARY OF DEFENSE, ASHTON CARTER, SAYING: "Both are stark reminders that North Korea is an up-close, dangerous and continuing threat to the security of the peninsula and the region, but together we will meet that threat." Carter is in Seoul for the 47th annual Security Consultative Meeting. Besides discussing their combined defence readiness against the North, the two ministers also agreed on a plan to transfer operational control of their combined troops from the U.S. to South Korea. They agreed that South Korea would need to improve its intelligence, surveillance, and reconnaissance capabilities before the transfer takes place. The US has more than 28,000 military personnel in South Korea.