The 16 mechanics spent the last two weeks in the central town of Rukla, several of them after receiving an introductory course in Germany.

"They acquired theoretical knowledge elsewhere, but... we taught them things from real life, what are the frequent failures which are not described in the textbooks," Zilvinas Cerskus, a major in the Lithuanian military, told AFP.

Lithuania has had the howitzers since 2016.

Berlin in June said it had begun supplying 155mm self-propelled howitzers to Ukraine.

Der Spiegel news magazine reported in November that they were experiencing severe wear and tear due to intensive firing of up to 300 rounds per day.

With no repair capacity in Ukraine, some of the howitzers were brought to NATO countries, including Lithuania.

Cerskus said the training would "save time and resources" since repairs can occur closer to the battlefield "instead of waiting for the repaired equipment to return from abroad for a month or two".

A Lithuanian military official who spoke to AFP on the condition of anonymity said lack of routine maintenance in some cases led to howitzer malfunctions in Ukraine.

Lithuanians trained 500 Ukrainian soldiers in various courses held this year, and next year hope to triple the number.

"It is the common enemy that motivates us," Cerskus said.