U.S. Secretary of State Antony Blinken visited a Ukrainian border guard site on the outskirts of Kyiv Thursday as he opened the final day of an unannounced two-day visit.

The tour included presenting four U.S.-provided mine-resistant ambush-protected vehicles that are part of a group of 190 of the vehicles to be delivered in coming months.

Blinken also met with a Ukrainian team working to clear unexploded Russian ordnance at a farm where corn was grown for export.

“What’s hard to get our minds around is that one third of Ukrainian territory has mines or unexploded ordnance on it,” Blinken said.  

“Your work is having a profound impact on the lives of Ukrainians and on people around the world,” he said, noting Ukraine’s importance to global food supply.

Blinken Wednesday announced $1 billion in new U.S. aid for Ukraine, with $175 million in security aid that includes additional air defense equipment, artillery munitions, anti-tank weapons including depleted uranium rounds for previously committed Abrams tanks, and other equipment.

Asked whether he is concerned about sustaining support for that level of U.S. aid among American citizens and lawmakers, Blinken was optimistic.

“I was last here almost exactly a year ago,” he said. “And in that time, in the year since I was last here, Ukraine has taken back more than 50% of the territory that Russia has seized from it since February 2022. In the current counteroffensive, we are seeing real progress over the last few weeks.”

Ukrainian Foreign Affairs Minister Dmytro Kuleba said what is being decided in this war is not just about Ukraine, but about what the world is going to look like after the war is over. If Russia wins, other autocrats will be empowered to invade their neighbors, he said, asking, ‘If the West cannot win this war, what war can they win?”

However, on Capitol Hill, one Republican senator expressed concerns to VOA, saying he would like to see a definitive strategy from the Biden administration for Ukraine to win the war.

“I’d like to see an announcement coming from all the NATO members saying that they are willing to step up. … I just got back from a trip to Europe, and we encouraged our NATO allies to actually step up their game, and I would like to see that happen,” Senator Bill Hagerty of Tennessee, a member of the Foreign Relations Committee, said.

The United States is the largest donor of military aid to Ukraine in total dollars. Other countries, including Denmark, Estonia, Latvia, Lithuania, Poland, Slovakia, Norway, Finland, the Netherlands, the United Kingdom and the Czech Republic, are making larger financial contributions to Ukraine relative to the size of their own economies, according to the Kiel Institute for the World Economy in Germany.

Some information in this report was provided by VOA congressional correspondent Katherine Gypson.