The United States is trying to speed up its deliveries of the $200 million worth of security assistance approved for Ukraine in December, Defense Department spokesperson John Kirby said Thursday.

"We are just at the beginning of a whole new package of assistance material," Kirby told a press briefing.

He revealed that there have been three shipments, and there is more to come. "We're trying to see if we can accelerate them."

He declined to disclose what each shipment contains, but he claimed they include lethal and non-lethal assistance designed to "help Ukraine defend itself."

Ukraine had received the first shipments of the US "lethal aid" earlier this week, which included Javelin anti-tank missiles.

Germany refusing to supply arms does not undermine unity: White House

The White House said it did not believe Germany's refusal to allow arms to Ukraine would impact unity among allies, Press Secretary Jen Psaki said.

"Unity does not require identical positions," Psaki underlined.

Germany blocked its NATO ally Estonia from providing Ukraine with German-made military equipment in light of the latter's efforts to strengthen its armed forces against the backdrop of concerns over Russia.

The new government in Berlin is continuing to pursue the previous administration's policy on the non-supply of weapons to Ukraine, reaffirming its commitment to the idea, German Chancellor Olaf Scholz said.

"We do not support the export of lethal weapons from Germany," Scholz told reporters following a cabinet meeting.

Berlin has been actively working toward a de-escalation of the situation around Ukraine, the chancellor highlighted, calling on Moscow to reduce its alleged military presence on the border.

On Saturday, the Ukrainian Foreign Ministry summoned German Ambassador Anka Feldhusen to express disappointment over Berlin's refusal to supply Kyiv with arms.

Germany argued that shipments of arms would not ease the conflict in eastern Ukraine.

"Our view is that unity does not mean [being] identical and that there are a range of capacities, capabilities, legal authorities that different countries have," Psaki said.

According to Psaki, the most important thing for the United States is "being united against the bellicose rhetoric, the buildup of troops and the potential of Russia invading the sovereign country of Ukraine."

The secretary praised Berlin, saying Washington found Germany to be "very much united with us" in that effort, as we have found with other European countries.

Mounting security concerns over Ukraine come as the West accuses Russia of planning an invasion of its western neighbor despite Russian dismissal.

Russia insists that it has no intention of attacking any country, and the Kremlin sees the Western accusations as a pretext to deploy more NATO military equipment close to Russia's borders.