"It does not only help to promise, and then you cannot deliver, or deliver things which do not work ... Some of our systems were really old-fashioned," Baerbock said in an interview with US media.
"So, because we know and we said that in the beginning, some are not really functioning, when we deliver, it does have to work in the field."
Weapons must be supplied to Ukraine together with ammunition, and the delays in shipments can be explained by the need for additional approvals, the top German diplomat told US media. Some of the equipment sent by Berlin also might have been non-functional because it was not accompanied by appropriate ammunition, she added.
Baerbock also said she could not give any information at present about whether Germany would supply Kiev with its Taurus cruise missiles, since it was necessary to be clear on every detail, including who could actually operate them, which "takes some time."