US Secretary of State Marco Rubio and Russia's Foreign Minister Sergei Lavrov spoke to discuss the next stage in talks on ending the Ukraine war.

According to State Department spokeswoman Tammy Bruce, the top diplomats on Saturday "agreed to continue working towards restoring communication between the United States and Russia."

The statement gave no details on when the next round of US-Russia talks, which are being hosted by Saudi Arabia, would begin.

Rubio also updated Lavrov on military activity in the Middle East, where US forces carried out deadly strikes against Houthis in Yemen, the statement said.

The US launched air strikes on Yemen, killing at least 20 people, as President Donald Trump warned that “hell will rain down” if the group continues attacks on Red Sea shipping.

Despite recent tensions between President Donald Trump and his Ukrainian counterpart, Volodymyr Zelenskyy, Kiev has agreed in principle to a US-brokered 30-day unconditional ceasefire if Moscow halts its attacks in eastern Ukraine.

Russia's President Vladimir Putin has not however agreed to any truce, instead setting conditions that were beyond what was called for in the US agreement with Ukraine.