U.S. President Donald Trump said on Monday that the United States will impose "very severe tariffs" on Russia in 50 days if there is no deal to stop the war in Ukraine.

Trump made the announcement of what he said would be a 100 per cent tariff rate while meeting with reporters alongside NATO Secretary General Mark Rutte in the Oval Office in Washington, D.C.

Trump said they would be "secondary tariffs," meaning they would target Russia's trading partners in an effort to isolate Moscow in the global economy. Direct trade between Washington and Moscow has plummeted since Russia launched its invasion in early 2022.

Trump also said the United States will send military aid to help Ukraine in its war effort, but that NATO members, not American taxpayers, would cover the cost of the weapons.

"We're going to make top-of-the-line weapons, and they'll be sent to NATO," he said. 

WATCH l Putin testing Trump's patience for lengthy ceasefire process, analysts say: 

What Russia wants in order to end its war in Ukraine

As peace negotiations drag on, Russia continues to pound Ukraine with missiles and drones. CBC’s Terence McKenna examines what it would take for Vladimir Putin to call off his war and why U.S. pressure doesn’t seem to be working.

Rutte said massive numbers of weapons would be sent, including missiles, as part of a first wave of equipment.

Trump said the equipment, including a Patriot missile system, would be arriving very soon.

U.S. envoy in Kyiv

The U.S. comments come after the Pentagon earlier this month ordered some military aid deliveries to Ukraine be turned around in Europe. Trump reversed that decision last week.

Trump had pledged to swiftly end the war on the 2024 presidential campaign trail, but months into his second administration, little progress has been made. The Republican president has sometimes criticized U.S. spending on Ukraine's defence, spoken favourably of Russia and publicly clashed with Ukraine President Volodymyr Zelenskyy.

At other times, he has expressed disappointment with President Vladimir Putin and Russia's continued bombardment of Ukraine.

"I'm very disappointed in President Putin, because I thought we would have had a deal two months ago, but it doesn't seem to get there," he said Monday.

While Trump was making his comments, Zelenskyy held talks with a U.S. envoy Keith Kellogg on increasing weapons production and arms purchases.

Zelenskyy, who has been seeking air defence systems to fend off Russian airstrikes, said on social media he had discussed "the path to peace and what we can practically do together to bring it closer" at talks with Kellogg.

WATCH l Atlantic Council senior fellow Michael Bociurkiw on the latest in the war: 

Atlantic Council senior fellow Michael Bociurkiw on the latest on Russia's war on Ukraine

Germany could be key ally

In addition to Rutte, German Defence Minister Boris Pistorius is set to visit Washington on Monday, for talks with Secretary of Defence Pete Hegseth.

Berlin has offered to pay for Patriot systems for Ukraine, under a proposal made public by Chancellor Friedrich Merz, and has emerged as an important player as European states in NATO move to build up their military strength under U.S. pressure.

Russia, which began its full-scale invasion in February 2022, holds about one-fifth of Ukraine. Its forces are slowly advancing in eastern Ukraine and Moscow shows no sign of abandoning its main war goals.

Putin told Trump by phone on July 3 that Moscow wants a negotiated end to the war but will not step back from its original goals, a Kremlin aide said.

A year ago, Putin was ready to halt the war with a negotiated ceasefire recognizing existing battlefield lines, Reuters reported at the time. But at talks last month, Russia set out punitive terms for peace, demanding Kyiv give up big new chunks of territory and accept limits on the size of its army.