NEW YORK — As some members of the Trump administration look to revive a long-dead plan to send weapons to Ukraine, three years into the country’s war against Russian-backed separatists, lawmakers in Ukraine are warning that they need help — and fast.

Concerns over Russia’s motives have only intensified in Kiev in the wake of its weeklong military exercises in neighboring Belarus, three senior Ukrainian party leaders told BuzzFeed News.

Andriy Teteruk, first deputy head of the People's Front’s party, the second-largest alliance in Ukraine’s parliament, said he believed Moscow would continue to push deeper into Ukrainian territory if Washington didn’t arm them soon.

“They have already surrounded Crimea, the east, and now Belarus,” he said, referring to long-planned war games that also have NATO anxious. “They have covered a third position on our country. It will be a very dangerous situation.”

Three years ago, Republicans lamented Obama’s decision not to arm Ukraine as “weak” and accused him of bowing down to Russian aggression — even senior Democrats criticized him. Donald Trump was also against a weapons package for Ukraine during his presidential campaign. But the idea has slowly regained steam within the Trump administration — which on Monday sided with Kiev to reject a Russian bid to introduce peacekeepers into Ukraine — with Ukrainian officials more hopeful than ever that Washington will make the deal happen.

US Defense Secretary James Mattis’s visit to Ukraine in August brought some hope to Ukrainian officials that a decision on whether to arm Ukraine with lethal weaponry would be coming soon. While Mattis has supported providing aid to Ukraine, he has not specified what exactly it would be if the White House does give the green light.

“We are actively reviewing it,” Mattis said during a joint news conference with Poroshenko.

One of the top items Ukrainian military officials have asked for is the FGM-148 Javelin, a portable anti-tank destroyer that has a reputation for being able to pierce most tanks' armor — including the T-90, a common Russian tank. Teteruk, an army veteran who sits on parliament’s committee on national security and defense, said the country’s military also wants advanced counterartillery radars that can identify enemy locations.

This hardware would have benefited the Ukrainian army in spring 2014, when Russian-backed rebels took over the Donbass and Luhansk regions in eastern Ukraine with the aid of superior Russian weaponry. The Obama administration responded with economic sanctions and provided military training to the Ukrainian military. But military and government officials in Kiev aggressively lobbied Washington for defensive weapons that could help the country’s soldiers repel rebel advances. President Obama declined to provide them, despite bipartisan support in Congress, over fears it would provoke Russia into advancing even further into Ukrainian territory.