Washington, DC – Some right-wing United States Republicans are slamming Joe Biden’s visit to Ukraine, invoking crises at home that they accuse the president of ignoring as he pledges support for Kyiv.

The opposition to Biden’s previously unannounced visit on Monday highlighted the views of a small but vocal cohort of ultraconservative US legislators who are sceptical of US support for Ukraine.

First-term Republican Congressman Andy Ogles accused Biden of prioritising “political field trips” on Monday.

“America-last Biden visited UKRAINE before visiting the people living through an environmental crisis in East Palestine, Ohio,” Ogles wrote on Twitter, referring to a toxic chemicals spill after a train derailment in Ohio earlier this month.

Still, the trip earned praise from Democrats who lauded Biden’s “leadership” in supporting Ukraine against the Russian invasion.

Many Republican critics noted that Biden left the country on Presidents’ Day, a US holiday honouring the country’s first president, George Washington. They also cited what they called a “crisis” at the US’s southern border, where record numbers of asylum seekers have arrived in recent months in search of protection.

“Today on our President’s Day, Joe Biden, the President of the United States chose Ukraine over America, while forcing the American people to pay for Ukraine’s government and war,” far-right firebrand Congresswoman Marjorie Taylor Greene said in a social media post.

Her fellow right-wing legislator Matt Gaetz quipped that Ukrainians “can keep” the US president.

“When our border is in crisis, Joe Biden goes home to nap in Delaware,” Gaetz wrote on Twitter.

“When Ohio burns with toxic chemicals, Biden’s admin says everything is fine. So on Presidents’ Day, I’m not surprised that Biden is ditching America for Ukraine.”

Biden announced $500m in additional aid to Ukraine during his trip on Monday, part of a growing tally of assistance in the billions of dollars that Washington has provided to Kyiv since the invasion started last year.

That continuing assistance has so far been approved by Congress with overwhelming bipartisan support.

Russia launched its all-out invasion of Ukraine on February 24 – nearly one year ago – after a months-long standoff that saw Moscow amass troops near the Ukrainian borders as Russian President Vladimir Putin demanded an end to NATO expansion into former Soviet republics.

Moscow’s war campaign has been mired by military setbacks, as Western powers continue to provide financial and military support to Kyiv. Russian officials have said that sending arms to Ukraine prolongs and intensifies the conflict.

“Breathtaking that President Biden can show up in Ukraine to ensure their border is secure, but can’t do the same for America,” Republican Congressman Scott Perry said in a tweet on Monday.

Most congressional Republicans still back US support for Ukraine, and many of them fault Biden for not being more aggressive against Russia.

But Ukraine’s supporters fear that “America First” isolationism may be gaining a greater foothold in conservative politics ahead of the 2024 presidential elections.

The Biden administration says it is committed to supporting Ukraine “as long as it takes” to help the country fight the Russian invasion.

US officials say the aid is necessary not only for the sake of Ukrainian allies but also to preserve rules against unprovoked wars and protect the international order.

In Kyiv, Biden described the Russian invasion as “brutal and unjust” as he met with Ukrainian President Volodymyr Zelenskyy.

“One year later, Kyiv stands, and Ukraine stands. Democracy stands,” Biden said. “The Americans stand with you, and the world stands with you.”

Back in the US, many Democrats lauded Biden’s visit to Kyiv, which came days before the first anniversary of the invasion.

Senator Cori Bush said in a social media post that Biden’s trip was a “reminder of the power of our presidency and how, when used responsibly, it can lift people up & be a beacon for freedom & democracy around the world”.

Adam Schiff, a key House Democrat, said he was “proud” to see Biden express Washington’s “unbreakable” support to Kyiv.

“We stand with the people of Ukraine in their struggle to push out Russian invaders, to enjoy the right of self-determination, and to live in peace,” Schiff wrote on Twitter.

Democratic Congressman Jason Crow dismissed the Republican criticism of Biden’s visit.

“These people know nothing about national security and foreign policy,” Crow told MSNBC.

“They don’t understand that it’s in our strategic interests and our security interests and the American people’s interests to have a stable, prosperous and free Europe and a free world, and that’s what this fight is about.”