Joe Biden’s $33bn request to Congress for more aid for Ukraine is likely to receive swift approval from lawmakers, a senior Republican said on Sunday, as the House speaker, Nancy Pelosi, made a surprise visit to the war-riven country.

The president on Thursday had asked for the money for military and humanitarian support for Ukraine as it fights to repulse the Russian invasion now in its third month.

Michael McCaul, a Texas Republican and ranking member of the House foreign affairs committee, went on ABC’s This Week with George Stephanopoulous and said he expected the chamber would look favorably on the request in the coming weeks.

McCaul’s comments came while Pelosi led a congressional delegation to Kyiv to meet the Ukrainian president Volodymyr Zelenskiy, and the House speaker promised on behalf of the US: “We are here until victory is won.”

McCaul was asked if he believed Congress would quickly pass Biden’s requested package, which includes $20bn in military aid, $8.5bn in economic aid to Kyiv and $3bn in humanitarian relief.

“Yes, I do,” McCaul said. “Time is of the essence. The next two to three weeks are going to be very pivotal and very decisive in this war. And I don’t think we have a lot of time to waste. I wish we had [Biden’s request] a little bit sooner, but we have it now.”

McCaul added that he believed Republicans, who have supported the Democratic president’s previous financial requests for Ukraine, might have acted more expediently if they held the House majority.

The chamber is not sitting during the coming week while members tend to in-district affairs, delaying debate and a vote on the aid package.

“If I were speaker for a day, I’d call Congress back into session, back into work,” he said.

“Every day we don’t send them more weapons is a day where more people will be killed and a day where they could lose this war. I think they can win it. But we have to give them the tools to do it.”

Meanwhile, Bob Menendez, the Democratic New Jersey senator who chairs the upper chamber’s foreign relations committee, echoed Pelosi’s pledge that the US would continue to support Ukraine financially.

“We will do what it takes to see Ukraine win because it’s not just about Ukraine, it’s about the international order,” he said on NBC’s Meet the Press.

“If Ukraine does not win, if [Russia’s president Vladimir] Putin can ultimately not only succeed in the Donbas but then be emboldened to go further, if he strikes a country under our treaty obligations with Nato, then we would be directly engaged.

“So stopping Russia from getting to that point is of critical interest to us, as well as the world, so we don’t have to send our sons and daughters into battle. That ability not to have to send our sons and daughters into battle is priceless.”

Menendez said that the US and its allies needed to “keep our eye on the ball” over a possible Russian move into Moldova’s breakaway region of Transnistria, where explosions were heard in recent days.

“I think that the Ukrainians care about what’s going to happen in Transnistria, because it’s another attack point against Ukraine,” he said.

“We need to keep our eye on the ball. And that is about helping Ukraine and Ukrainians ultimately being able to defeat the butcher of Moscow. If we do that, the world will be safer. The international order will be preserved, and others who are looking at what is happening in Ukraine will have to think twice.”

Samantha Power, administrator of the US Agency for International Development (USAID), laid out the urgent need for Congress to approve the package during an interview on CBS’s Face the Nation.

“There are vast swaths of Ukraine that have been newly liberated by Ukrainian forces, where there is desperate need, everything from demining to trauma kits to food assistance, since markets are not back up and running,” she said, noting that from previously approved drawdowns “assistance is flowing”.

But she said that 40 million people could be pushed into poverty, and demands for help would only grow.

“We’re already spending some of that money, but the burn rate is very, very high as prices spiral inside Ukraine and outside Ukraine,” Power said. “So that’s why this supplemental is so important. It entails $3bn of humanitarian assistance to meet those global needs, which are famine-level, acute malnutrition needs.

“And it includes very significant direct budget support for the government of Ukraine, because we want to ensure the government can continue providing services for its people.”

“Putin would like nothing more than the government of Ukraine to go bankrupt and not be able to cater to the needs of the people. We can’t let that happen.”