Washington DC - President Donald Trump on Tuesday again expressed his frustration with his Russian counterpart, Vladimir Putin, just days before Ukraine's Volodymyr Zelensky is due to visit Washington.

"I'm very disappointed, because Vladimir and I had a very good relationship. Probably still do," Trump told reporters at the White House. "I don't know why he continues with this war."

The Republican seemed to mock Putin for nearing the four year-mark in a conflict that "he should have won... in one week."

"And I think it's making him look very bad. He could end it. He could end it quickly," the Republican complained.

At the same time, Trump praised Ukraine for holding out against Russia – a complete change in posture from his earlier hostility to the embattled country.

He also confirmed that Zelensky would visit him on Friday.

"He wants weapons. He would like to have Tomahawks," Trump said of Ukraine's president.

The 79-year-old has not ruled out supplying Kyiv with Tomahawk cruise missiles, though he previously said he wanted to use that possibility as leverage in talks with Russia.

Kremlin spokesperson Dmitry Peskov on Monday explicitly warned the US against making such deliveries.

Tomahawk cruise missiles have a range of over 1,500 miles and can technically be equipped with nuclear warheads.