Kevin McCarthy, the California Republican who became House speaker in January, made a public promise on Monday to continue supporting Ukraine’s war effort, walking back previous suggestions that the new House majority might curtail U.S. military and financial investments in Kyiv’s effort to beat back Russia’s invasion.

Speaking at a news conference in Jerusalem shortly after delivering a speech to Israel’s Knesset, Mr. McCarthy pushed back forcefully after a reporter for the Russian state news agency RIA Novosti questioned him about whether he might pull back on aid and weaponry for Ukraine.

“I vote for aid for Ukraine, I support aid for Ukraine,” Mr. McCarthy said to the reporter, who had prefaced his question by stating, “We know that you don’t support the current unlimited and uncontrolled supplies of weaponry and aid to Ukraine.”

Mr. McCarthy, who has previously said that there would be no “blank check” for Ukraine, then added a sharp condemnation of Russia’s actions in the conflict.

“I do not support what your country has done to Ukraine; I do not support your killing of the children either,” Mr. McCarthy told the Russian reporter. “And we will continue to support, because the rest of the world sees it just as it is.”

The statements stood in sharp contrast to Mr. McCarthy’s recent signals regarding assistance for Ukraine, amid pressure from far-right Republican lawmakers to audit U.S. support for Kyiv and cut off American funding for the conflict.

Mr. McCarthy’s words prompted a flood of cheers from Republican hawks, including former Vice President Mike Pence, who thanked Mr. McCarthy in a tweet “for calling out Russia with conviction on the world stage.”

Mr. McCarthy’s pledge could put him in an awkward position with a small but critical faction of his conference that has vocally opposed further funding for Ukraine in the war.

That band of mostly ultraconservative Republicans includes several House members who voted to deny Mr. McCarthy the speaker’s gavel during several successive ballots at the beginning of the year. It also includes the right-wing representative Marjorie Taylor Greene of Georgia, who has become one of Mr. McCarthy’s closest allies.

In recent weeks, as Republicans have attempted to coalesce around a plan to cut spending in advance of debt ceiling negotiations with the White House, Ms. Greene has been waging a steady campaign against continuing military assistance and other forms of aid for Ukraine.

She has called for zeroing out that part of the budget, charging that the Biden administration has been “swindled” by the Ukrainian president, Volodymyr Zelensky, and arguing that the assistance being provided is making the United States too active a participant in the country, stating, “Ukraine is not the 51st state.”

Under pressure from Ms. Greene and others, Mr. McCarthy has recently been sparing in his public comments about Ukraine. Last month, the speaker declined to share details about a phone call with Mr. Zelensky, noting simply that it was a “good conversation.”

But Ukraine skeptics on the right recently lost one of their most effective platforms for communicating their view to voters, after Fox News fired Tucker Carlson. Mr. Carlson, who promoted a similar view about Ukraine from his prime-time slot, had given Ms. Greene and others a regular platform to address millions of Republican-leaning viewers, a means of maintaining pressure on Mr. McCarthy.