US Secretary of State Antony Blinken and US Defense Secretary Lloyd Austin have arrived in Kyiv and were holding talks with Ukrainian President Volodymyr Zelenskyy, and adviser to Zelenskyy said late on Sunday in a social media video, according to Reuters.

The trip by Blinken and Austin, announced earlier by Zelenskyy, is the highest-level visit to Ukraine by US officials since Russian President Vladimir Putin ordered the invasion of the country on February 24.

Ahead of the meeting on Sunday, Zelenskyy's aide Igor Zhovkva told NBC News that Ukrainian officials were planning to tell Blinken and Austin of the immediate need for more weapons, including anti-missile systems, anti-aircraft systems, armored vehicles and tanks.

"Tomorrow we will discuss this exact list of weapons that are essential for us and the pace of deliveries," Zelenskyy said in a Saturday evening news conference.

The visit by the top US officials comes days after US President Joe Biden announced a new package of $800 million in military aid for Ukraine.

The Pentagon said the newest round of US support will include 72 155mm howitzers, 72 armored vehicles to tow them, 144,000 rounds of ammunition, and more than 120 "Phoenix Ghost" tactical drones recently developed by the US Air Force specifically to address Ukraine's needs.

The new package followed $800 million in military assistance announced by the White House a week earlier, taking to $4 billion the amount the US has put up in arms and supplies for Ukraine's forces since the start of the Biden administration in January 2021.

The latest US aid to Ukraine came several days after Zelenskyy said that Russian forces had begun a new offensive in eastern Ukraine.

“We can now say that Russian forces have started the battle of the Donbas, for which they have long prepared,” he said in a video address.

“No matter how many soldiers are drawn there, we will defend ourselves. We will fight. We will not give up anything Ukrainian,” he stated.