Western leaders have equipped their allies in Ukraine with arms to defend themselves throughout the invasion. However, they have held back many of their most advanced weapons. Now, they say a new level of "combat power" may be required to push Russian forces out.

US Defense Secretary Lloyd Austin met with German Defense Minister Boris Pistorius on Thursday. It was Pistorius' first day on the job. Both find themselves under pressure to deliver advanced tanks but, as one Pentagon official said, they are not yet prepared to meet Ukraine's calls.

NATO leaders need permission from Germany to provide the Ukrainians with German-made Leopard 2 tanks. Ukrainian President Volodymyr Zelenskyy says officials in Poland, Finland and other countries are ready but are still waiting.

Zelenskyy said, "The bravery of our servicemen and the motivation of the Ukrainian people is not enough to oppose the thousands of tanks of the Russian Federation. We need weapons."

British leaders have promised to send in their main battle tank. They said in a statement with other allies that they want to provide an "unprecedented set of donations."

Defense officials from about 50 Western countries fear the Russians may be preparing for a new offensive. They will meet at an air base in Germany on Friday to discuss another round of military aid.

On Thursday, Russian Foreign Minister Sergey Lavrov accused Western leaders of creating a direct threat to his country's interests.

Lavrov said, "I hope they will sober up. At least we will do everything for our colleagues from NATO and the EU to sober up, as soon as possible.