Speaking a day after President Donald Trump spoke by telephone to Russian counterpart Vladimir Putin and the US administration said Ukraine would have to cede territory, Rubio said the US has a “stake in Ukraine’s long-term independence.”

“That should be anchored in an ongoing economic interest,” Rubio told the radio show of conservative hosts Clay Travis and Buck Sexton.

“Hopefully we’ll have some news here soon on that: the ability to partner with Ukraine – a joint venture, or something like that – for their mineral rights, all the natural resources they have,” he said.

“Some of that money will go back to pay back the US taxpayer for the billions of dollars that’s been spent there,” Rubio added.

“Part of it is going to be reinvested back into Ukraine to rebuild (from) all the destruction that’s happened there.”

Rubio on Thursday also spoke by telephone with Ukrainian foreign minister Andriy Sybiga, who has warned that Russia is trying to divide up the world in a similar way to the Yalta conference, where the Soviet, US and British leaders discussed the balance of power after World War II.

Rubio in the call discussed “bold diplomacy to end the war in a negotiated manner leading to a sustainable peace,” state department spokeswoman Tammy Bruce said.

Trump, long critical of the money sent to Ukraine since it was invaded by Russia, earlier this month suggested that he wanted an agreement to access Ukraine’s rare earth material as a condition to sustain support.

Ukraine has major resources of lithium and titanium that are critical to high-tech technologies including aerospace and electric vehicles.