NATO countries have agreed to give Ukraine more air defences after desperate pleas from Kyiv for advanced systems to shoot down Russian attacks, alliance chief Jens Stoltenberg said Friday.

"NATO defence ministers have agreed to step up and provide further military support, including more air defence," Stoltenberg said after virtual talks with Ukrainian President Volodymyr Zelensky.

"NATO has mapped out existing capabilities across the alliance and there are systems that can be made available to Ukraine," he said.

"So I expect new announcements on air defence capabilities for Ukraine soon."

Ukraine has been urgently calling on its Western backers to send more air defences as it has struggled to fend off a surge in Russian attacks on its infrastructure in recent weeks.

Kyiv has above all been calling for more US-designed Patriot systems that are capable of shooting down Russian hypersonic missiles.

Stoltenberg said there were Patriot and also Franco-Italian SAMP/T systems available in stocks of NATO countries that can be given to Ukraine.

But he could not say whether NATO defence ministers had made concrete commitments during the meeting.

Germany earlier this week announced it was giving Ukraine an additional Patriot system, on top of two already supplied.

Officials say that the United States, Germany, Netherlands, Spain, Greece, Romania and Poland are the NATO countries with Patriot systems.

US lawmakers will vote Saturday on a long-stalled $61-billion aid package for Ukraine that allies hope will reopen a stream of support from Washington.

"I count on the bill to pass without further delay," Stoltenberg said.

The hold-up in support from Washington and struggles by Europe to find enough weaponry have left outgunned Ukrainian forces struggling to hold back Moscow's troops.

Stoltenberg said that ministers also discussed Kyiv's "many other pressing needs", including artillery shells, longer range missiles and drones.

"Each NATO ally will decide what to provide. Several allies made concrete commitments during the meeting and are finalising contributions that I expect will be announced soon," he said.