US President Donald Trump told his Russian counterpart Vladimir Putin on Wednesday to make a deal to end the grinding Ukraine war "now" or face tariff hikes and more sanctions.

"If we don't make a 'deal', and soon, I have no other choice but to put high levels of Taxes, Tariffs, and Sanctions on anything being sold by Russia to the US, and various other participating countries," Trump said on his Truth Social network.

The US President said he was "not looking to hurt Russia" and had "always had a very good relationship with President Putin," a leader for whom he has expressed admiration in the past.

"All of that being said, I'm going to do Russia, whose Economy is failing, and President Putin, a very big FAVOR. Settle now, and STOP this ridiculous War! IT'S ONLY GOING TO GET WORSE."

"Settle now, and stop this ridiculous war! It's only going to get worse. If we don't make a "deal," soon, I have no other choice but to put high levels of taxes, tariffs, and sanctions on anything being sold by Russia to the United States, and various other participating countries. Let's get this war, which never would have started if I were President, over with! We can do it the easy way, or the hard way - and the easy way is always better. It's time to 'make a deal.' No more lives should be lost," Trump added.

Trump was taking a harder line than he had during a White House press conference on Tuesday when he said it "sounds likely" that he would apply additional sanctions if Putin did not come to the table.

The US President also declined to say whether he would continue his predecessor Joe Biden's policy of sending weapons to Ukraine to fight off Russia's invasion, launched in February 2022.

"We're looking at that," he said at the press conference.

"We're talking to (Ukrainian President Volodymyr) Zelensky, we're going to be talking to President Putin very soon."

Before his inauguration on Monday, Trump had vowed to end the Ukraine war before even taking office, raising expectations he would leverage aid to force Kyiv to make concessions to Moscow.

In unusually critical remarks of Putin on Monday, Trump said the Russian President was "destroying Russia by not making a deal".

Trump added that Zelensky had told him he wanted a peace agreement to end the war.

Whatever route Trump chooses, he is unlikely to execute it before speaking with Putin, firm in his belief that direct communication could lead to positive results.

A call between the men will happen "very soon," Trump said this week.