President Donald Trump said on Tuesday he has raised with Russian President Vladimir Putin the issue of Stephen Hubbard, a retired American school teacher held by Moscow, and hinted that a development in the case could happen soon.

Trump made the comment to reporters in the Oval Office as US envoy Steve Witkoff prepared to go to Moscow for more talks about Ukraine after meeting Ukrainian President Volodymyr Zelenskiy in Oslo on Tuesday.

In his remarks, Trump piled more pressure on Zelenskiy to make a deal with Russia to end Moscow’s four-year war in Ukraine.

“Ukraine has to want to settle this war,” Trump told reporters in the Oval Office.

Trump suggested Moscow had the upper hand in the fight because “Russia is a big machine – they just keep grinding forward, and that’s what they’ve done. They’ve taken a very large piece of land.”

Trump, asked about the case of Hubbard, said he had been talking to Putin about the American, who has been declared wrongfully detained by the State Department.

“Just stick with me,” said Trump. “I don’t want to talk about it, but everybody has been after Hubbard for a long time, long before I got here. And just remember that question for a couple of days from now, okay? Because I do things that nobody else can do. ”

“Watch what happens. We have been focused on Hubbard,” he said.

Hubbard, 74, is serving a nearly seven-year sentence in a Russian penal colony on mercenary charges.

(Reporting by Steve Holland; Editing by Caitlin Webber and David Ljunggren and Michelle Nichols )