SEOUL/MANILA: US Secretary of State Rex Tillerson held a door open for dialogue with North Korea on Monday, saying Washington was willing to talk to Pyongyang if it halted a series of recent missile test launches.

Tillerson's comments, made at a regional security forum in Manila, were the latest US attempt to rein in Pyongyang's nuclear and missile program after months of tough talk from US President Donald Trump .

The UN Security Council on Saturday imposed its toughest round of sanctions yet against Pyongyang over its two intercontinental ballistic missile tests in July.

But Tillerson appeared more conciliatory on Monday.

"When the conditions are right, then we can sit and have a dialogue around the future of North Korea so they feel secure and prosper economically," Tillerson told reporters.

"The best signal that North Korea can give us that they are prepared to talk would be to stop these missile launches," said Tillerson, adding that "other means of communications" were open to Pyongyang.

There was no direct reaction from North Korea to Tillerson's remarks but in a statement after the U.S. secretary of state made his comments, Pyongyang responded robustly to the new sanctions by saying it was ready to teach the United States a "severe lesson" if it attacked.

The UN Security Council unanimously imposed sanctions on North Korea aimed at pressuring Pyongyang to end its nuclear programme. The sanctions could further choke North Korea's struggling economy by slashing its $3 billion annual export revenue by a third.

The United States has remained technically at war with North Korea since the 1950-53 Korean conflict ended in an armistice rather than a peace treaty. The past six decades have been punctuated by periodic rises in antagonism and rhetoric that have always stopped short of a resumption of active hostilities.

The Trump administration's attempts to pressure North Korea into abandoning its nuclear and missile ambitions have so far gained little traction, and Pyongyang has only stepped up its tests, launching two intercontinental ballistic missile tests last month.

Tillerson's remarks might be an attempt to try another tack by the United States, which also has tried to get Pyongyang's ally China to use its influence to prevent North Korean leader Kim Jong Un from building a nuclear arsenal.

Tillerson said halting missile test launches, which have worried neighbors South Korea and Japan, was a first step toward dialogue.

"We’ve not had an extended period of time where they have not taken some type of provocative action by launching ballistic missiles."

He said Washington would not "specify a specific number of days or weeks" before deciding that North Korea had indeed halted its tests.

TOUGH SANCTIONS

The UN resolution bans North Korean exports of coal, iron, iron ore, lead, lead ore and seafood. It also prohibits countries from increasing the current numbers of North Korean labourers working abroad, bans new joint ventures with North Korea and any new investment in current joint ventures.

Tillerson said the support of China and Russia for the latest sanctions sent a strong message to North Korea about what was expected of it.

Chinese Foreign Minister Wang Yi urged "the North Korean side to calmly handle the resolutions". He said in Manila on Sunday that Pyongyang should "not do anything unbeneficial towards the international community such as a nuclear test."

In a statement to the Manila forum on Monday, Pyongyang said it would never place its nuclear programme on the negotiating table as long as the United States maintained a hostile policy against the North.

It noted its intercontinental ballistic missile tests last month proved the entire United States was in its firing range.

North Korea says it ICMBs are a legitimate means of defense. It has long accused the United States and South Korea of escalating tensions by conducting military drills.

China's Wang said the core of the Korean Peninsula issue is a security issue, not an economic issue, as North Korea believes it faces an external security threat, while other parties believe Pyongyang's nuclear and missiles programmes are a threat.

During an hour-long phone call, South Korea's Moon and Trump said they would continue cooperating to rein in North Korea, particularly ahead of a regular joint military drill set for late August, South Korean presidential office spokesman Park Su-hyun said.

The White House said the two leaders "affirmed that North Korea poses a grave and growing direct threat" to most countries around the world. In a Twitter post, Trump said he was "very happy and impressed with 15-0 United Nations vote" on the sanctions.

