German Defence Minister Christine Lambrecht announced the plan at a NATO meeting today (June 15). Dozens of defence ministers from NATO countries and other parts of the world are expected to discuss weapons deliveries to Ukraine at the meeting in Brussels.
Kyiv has called for a significant boost to its arms to help fend off Russian forces.
Ukrainian presidential adviser Mykhailo Podolyak said on Monday that Ukraine needs 1,000 howitzers, 500 tanks and 1,000 drones among other heavy weapons.
German media reports that Berlin wants to supply Ukraine with three Mars II launchers instead of the four which had been under discussion.
From Bundeswehr stocks, the launchers will reportedly be ready for delivery in August or September. The Mars II multiple rocket launcher can hit targets at a distance of more than 80 kilometres.
The pledge to deliver three is in part due to a lack of ammunition. The US is reportedly going to send extra ammo for the launchers which can provide more precise targeting.
As well as the launchers, Germany is due to send seven, self-propelled howitzers to Ukraine in June with 30 Gepard anti-aircraft tanks to follow from July.
Wednesday’s NATO meeting is being led by US Defence Secretary Lloyd Austin.
It is the third time the group of almost 50 countries is meeting to discuss and coordinate help for Ukraine.
Mr Austin said: “We can’t afford to let up and we can’t lose steam. The stakes are too high.
“We must intensify our shared commitment to Ukraine’s self-defence and we must push ourselves even harder to ensure that Ukraine can defend itself, its citizens, and its territory.”
Washington has committed about £3.8 billion ($4.6bn) in security assistance to Ukraine since Russia invaded on February 24.
This includes artillery systems such as howitzers and longer-range weapons like the High Mobility Artillery Rocket System (HIMARS).
A senior US defence official, speaking on the condition of anonymity, told news agency Reuters: “Russia has not given up on the fight, despite its pretty anemic progress… What we have is this grinding, slow, incremental Russian operation.
“So the question is what do the Ukrainians need to continue the success they’ve already seen in slowing down and thwarting that Russian objective and that’ll be a major focus for the defence ministers.”
US President Joe Biden’s administration has said it has received assurances from Kyiv that longer-range weapons will not be used to attack Russian territory.
Kyiv has said it is losing 100 to 200 soldiers every day with hundreds more wounded.
In an overnight address, President Volodymyr Zelensky described the battle for the eastern Donbas region – partly occupied by Moscow’s proxies since 2014 – as one of the most brutal in European history.
Additional reporting by Monika Pallenberg