"Our defence ministers will sign a memorandum of understanding today regarding the procurement of Ukrainian-made long-range weapons systems," said Merz, without naming the manufacturers involved.

"There will be no range restrictions, allowing Ukraine to fully defend itself, even against military targets outside its own territory," he told a joint press conference.

Merz, who took power early this month, has vowed to keep strongly backing Ukraine, but without giving details of which weapons Germany is sending, in line with a policy of strategic ambiguity.

The production of long-range weapons "can take place both in Ukraine and here in Germany," he said. "We will not provide any further details until further notice."

Merz hailed the project as "the beginning of a new form of military-industrial cooperation between our countries that has great potential".

"Both defence ministers are working closely together in this area. We want to enable long-range weapons. We also want to enable joint production, and we will discuss some of these things privately," he said.

Merz had pointed out in a TV interview this week that already "there are no longer any range restrictions on weapons delivered to Ukraine -- neither by the British nor by the French nor by us nor by the Americans".

"This means that Ukraine can now defend itself, for example, by attacking military positions in Russia... With very few exceptions, it didn't do that until recently. It can now do that."