WASHINGTON — U.S. Secretary of State Antony Blinken arrived in Kyiv on Wednesday, his fourth trip to the war weary country since Russia’s full-scale invasion last year.

A senior State Department official described the unannounced visit to Kyiv as one intended to remind people that “dictators and autocrats” were not able “to bite off a piece of their neighbor and get to keep it with impunity,” Reuters reported, saying the official had spoken on condition of anonymity..

During the two-day visit, Blinken with key Ukrainian officials, including President Volodymyr Zelenskyy, Prime Minister Denys Shmyhal and Foreign Minister Dmytro Kuleba.

Blinken’s trip comes amid a burst of battlefield gains recently by Ukrainian forces, who are carrying out a counteroffensive in the South and East of the country.

In the 72 hours before Blinken arrived, Ukrainian soldiers made “notable progress” in southern Zaporizhzhia, the White House said.

“Where they go from here, and how they exploit that success, I’ll leave it to them to discuss,” National Security Council spokesman John Kirby told reporters on a Sept. 1. conference call.

Kirby declined to provide additional details, citing operational security risks.

The trip also comes amid an escalating debate in Congress over how much, and for how long, America intends to support Kyiv. Some Republicans are voicing concern over the massive outpouring of U.S. aid to Ukraine.

The U.S. has pledged more than $43 billion in military, financial and humanitarian aid since the nation was invaded. Blinken was expected to announce an additional $1 billion in aid on Wednesday.

Read more: Ukraine war divides Republicans heading into first GOP debate

The Kremlin claimed Blinken’s visit to Kyiv was proof that the U.S. was willing to fund the war “to the last Ukrainian.”

“We have repeatedly heard statements that they [the U.S.] intend to continue helping Kyiv for as long as it takes,” Kremlin spokesman Dmitry Peskov said during a press briefing Wednesday.

Russia has frequently framed the war in Ukraine as a proxy war with the West, blaming the roots of the conflict, which began after Russia invaded its neighbor in Feb. 2022, on Ukraine’s Western allies.