Image copyright Reuters Image caption Rex Tillerson is in China meeting President Xi Jinping and other top officials

The US is in "direct contact" with North Korea, Secretary of State Rex Tillerson has said.

Mr Tillerson said Washington was "probing" the possibility of talks with Pyongyang, "so stay tuned".

"We have lines of communications to Pyongyang," he said during a trip to China. "We're not in a dark situation."

North Korea and the US have engaged in heated rhetoric in recent months but it was not previously known they had lines of communication.

The US state department later confirmed there were a number of communication channels open with Pyongyang, but said little progress was being made.

"Despite assurances that the United States is not interested in promoting the collapse of the current regime (...) North Korean officials have shown no indication that they are interested in or are ready for talks regarding denuclearisation," department spokeswoman Heather Nauert said in a statement.

Media playback is unsupported on your device Media caption North Koreans rally against "dotard psycho Trump"

The US wants North Korea to halt its weapons programme, which has seen it perform repeated missile tests and, on 3 September, the test of a miniaturised hydrogen bomb which could be loaded on to a long-range missile, which Pyongyang said was successful.

But attempts at dialogue seem to be at odds with President Donald Trump's own attitude to the issue. Just last month, he said "talking is not the answer".

Mr Trump has previously threatened to annihilate North Korea, saying the country's leader, Kim Jong-un, "is on a suicide mission". Mr Kim then vowed to "tame the mentally deranged US dotard with fire".

North Korea continued the rhetoric on Saturday, releasing a statement calling Mr Trump an "old psychopath" bent on the "suicidal act of inviting a nuclear disaster that will reduce America to a sea of flames".

The UN has brought in sanctions against North Korea in an attempt to force the secretive state to stop its weapons programme.

Media playback is unsupported on your device Media caption Trump: 'Rocket Man's suicide mission'

The US sees China - North Korea's biggest trading partner - as key to ensuring the sanctions are effective.

China this week told North Korean businesses operating in its territory to close down. However, China remains keen to see negotiations with North Korea.

Mr Tillerson revealed the communications channels following a meeting in Beijing with President Xi Jinping and other officials.