South Korea's coast guard said Monday it is drawing up guidelines on how to inspect North Korean ships suspected of carrying banned items — a move expected to enrage Pyongyang, which has warned it would consider such inspections a declaration of war.

The move came as a senior U.S. diplomat met with South Korea's nuclear envoy about implementing U.N. sanctions punishing Pyongyang for its latest nuclear test and getting the communist regime to return to talks on its nuclear program.

Kurt Campbell, the assistant secretary of state for East Asia and Pacific affairs, also held talks in Japan and goes Monday to Thailand for Asia's main security conference, where North Korea should be a key topic.

"We need to make sure that we're extremely closely coordinated in a very critical period ahead," Campbell said at the start of a meeting with Seoul's nuclear envoy, Wi Sung-lac.

Wi said the two allies should work closely together to implement the U.N. sanctions, which include ship searches, and resume stalled nuclear talks.

North Korea quit the talks aimed at ending its nuclear ambitions in April in anger over a U.N. rebuke after it launched a long-range rocket. It also conducted a nuclear test in May and a series of banned ballistic missile tests early this month.

Campbell said Saturday there should be consequences for North Korea's provocations, but said the U.S. and its partners would be prepared to offer attractive incentives if Pyongyang returned to the talks and took "serious and irreversible steps" to disarm.

The stalled talks involved China, Japan, the two Koreas, Russia and the U.S.

Pyongyang's No. 2 leader, Kim Yong Nam, said last week that the talks are permanently over because the U.S. and its allies do not respect North Korea's sovereignty.

South Korea's move to draw up the ship inspection guidelines is in line with latest U.N. sanctions that clamp down on North Korea's alleged trading of banned arms and weapons-related material, a key source of hard currency for the impoverished nation.

A coast guard official said the guidelines would call for inspecting North Korean ships traveling in South Korean waters if there is concrete evidence they carry banned items. The official, who spoke on condition of anonymity citing the issue's sensitivity, did not give details.

A North Korea ship suspected of heading toward Myanmar with a cargo of banned items turned back home earlier this month after surveillance by the U.S. Navy as part of the U.N. resolution.

The latest resolution toughened sanctions called for in a 2006 resolution adopted after the North's first nuclear test. That resolution bans countries from exporting luxury goods to North Korea — a clause targeting the regime's ruling elite.

Under the ban, Italian police have seized two luxury yachts that North Korean leader Kim Jong Il ordered from an Italian shipbuilder, the daily Libero reported Friday. The paper said European financial authorities also confiscated in early April millions of dollars in deposits for the yachts.

The security conference opening Wednesday in Thailand brings together foreign ministers and senior diplomats from 27 countries, including U.S. Secretary of State Hillary Rodham Clinton. North Korea is sending a lower-level official, instead of the foreign minister, to the meeting.