BEIJING -- North Korea's top diplomat arrived in China on Saturday en route to the Philippines for a regional security conference, a source said, amid a looming vote that could tighten sanctions on Pyongyang for its missile and nuclear programs.

Foreign Minister Ri Yong-ho and four other North Korean officials will take a connecting flight to Manila for the ASEAN Regional Forum, according to the source.

North Korea's official Korean Central News Agency said the North Korean delegation left Pyongyang for the security conference in the Philippines. No details were given.

The high-stakes conference comes as the UN Security Council prepares to vote on a resolution imposing tougher sanctions on North Korea for its recent intercontinental ballistic missile tests.

The US-drafted resolution aims to cut North Korea's export revenue by one-third to $1 billion a year, according to news reports.

The vote -- scheduled to start at 3 p.m. on Saturday (New York time) -- is widely expected to pass the council as Washington struck an agreement with Beijing and probably Moscow.

Securing consent from China and Russia is key as they are two of the five permanent veto-wielding members of the UN Security Council.

North Korea's main newspaper, the Rodong Sinmun, said neither sanctions nor military threats will work on the North. "War rackets and extreme sanctions trumpeted by the US warmongers would rather embolden the DPRK to bolster up its nuclear force," the newspaper said in an article carried by the KCNA, using the acronym for the Democratic People's Republic of Korea, North Korea's official name.

The US said Secretary of State Rex Tillerson has no plans to meet with Ri on the sidelines of the ARF, the only yearly event in which the top North Korean and American diplomats take part.

In 2004, then-North Korean Foreign Minister Paik Nam-sun had an informal, 20-minute meeting with then-US Secretary of State Colin Powell during the ARF in Jakarta.

ASEAN comprises Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Thailand, Singapore and Vietnam.