Washington, Jul 16 (AP) President Donald Trump has downplayed the possibility of sending Ukraine long-range weapons as Kyiv awaits an injection of US weaponry that it hopes will help it beat back an intensifying Russian air offensive.

Trump on Tuesday offered a more cautious tone on what to expect after he threatened Russia a day earlier with steep tariffs if President Vladimir Putin doesn't act within 50 days to end the three-year conflict. He also on Monday announced plans to bolster Kyiv's stockpile by selling American weapons to NATO allies who would in turn send arms to Ukraine.

Providing Ukraine with more long-range weaponry would give Kyiv the chance to strike further into Russian territory, a move that some in Ukraine and the US have said could help push Putin toward negotiations to end the fighting.

Asked if he intended to supply Ukraine with weapons that could reach deeper into Russian territory, Trump replied, "We're not looking to do that." He made the remarks to reporters before departing the White House for an energy investment event in Pittsburgh.

While Trump's threats of weapons, sanctions and tariffs mark the most substantive pressure he's placed on Putin since returning to office nearly six months ago, some lawmakers said they remain concerned that the administration, with the 50-day deadline, is giving Putin time to grab even more Ukrainian territory.

Sens. Thom Tillis, a Republican from North Carolina, and Jeanne Shaheen, a Democrat from New Hampshire, said waiting 50 days before imposing sanctions on Russia would give Putin more time to gain an advantage in the war.

"The 50-day delay worries me that Putin would try to use the 50 days to win the war, or to be better positioned to negotiate a peace agreement after having murdered and potentially collected more ground," said Tillis, who recently announced he won't run for re-election.

Tillis and Shaheen lead the Senate NATO Observer Group, which facilitates work between Congress and NATO, and met Tuesday with NATO Secretary General Mark Rutte on Capitol Hill.

Trump himself scoffed at the idea that 50 days is giving Putin too much time. The president suggested he may act more quickly if he does not see signs that Putin is taking steps toward ending the conflict.

"I don't think 50 days is very long and it could be shorter than that," he said.

Ahead of Trump's announcement that he would impose a 100 per cent tariff on Russia's trading partners if Putin doesn't negotiate an end to the war, bipartisan legislation proscribing even tougher sanctions on Moscow was gaining steam in the Senate.

The legislation, in part, calls for a 500 per cent tariff on goods imported from countries that continue to buy Russian oil, gas, uranium and other exports. It would have an enormous impact on the economies of Brazil, China and India, which account for the vast majority of Russia's energy trade.

But Trump on Monday said "at a certain point it doesn't matter" how high the tariff is set and that "100 per cent is going to serve the same function". Senate Majority Leader John Thune said he was putting the legislation on hold following Trump's announcement.

Trump during his campaign described the conflict as a waste of US taxpayer money and vowed to quickly end it on his first day back in office. He deflected when asked by a reporter on Tuesday if his tougher tone on Putin suggests he's now on Ukraine's side in the bloody conflict.

"I'm on nobody's side," Trump said, adding this concern was for "humanity".

US officials say they are still sorting through Ukraine's wish list of weaponry to determine what can be most quickly replaced after Trump announced an agreement for Europe to supply Ukraine with defensive munitions from existing stocks.

The officials, who spoke on condition of anonymity to discuss arms transfers that have not yet been approved or completed, said Ukraine's requests for military equipment are roughly the same as they have been since the start of Russia's invasion. Those include air defences like Patriot missiles and Advanced Precision Kill Weapon Systems, long-range missiles known as ATACMS and short- to medium-range ground-to-air missiles known as NASAMs, and assorted artillery, according to the officials.

Under the terms of the very rough agreement sketched out by Trump and Rutte on Monday, NATO members would ship billions of dollars of these weapons to Ukraine and then purchase replacements for them from the United States.

One official said some of the larger items — such as Patriots — could take up to five years to produce to deliver to the European donors, while smaller munitions like 155 mm artillery shells can be produced on a much shorter timeline.

Trump has lately changed his once friendly tune toward Putin, whom he has long admired and whom he sided with publicly over his national security team during his first term when asked whether Russia had interfered in the 2016 election.

In recent weeks, Trump has chastised Putin for continuing his brutal assault on Ukrainian cities, even noting that the Russian leader "talks nice and then he bombs everybody". (AP) DIV DIV