BERLIN, Aug 8 (Reuters) - Germany has offered to extend the deployment of three Patriot air defence units in Poland until the end of 2023, the defence ministry in Berlin said on Tuesday (Aug 8).

"An extension beyond the end of 2023 is not foreseen," the ministry said in a statement, adding that some of Germany's Patriot units were needed for use by NATO's quick reaction response force in 2024, while others had to undergo maintenance.

Together with three Patriot air defence units, some 300 German soldiers have been based in the Polish town of Zamosc, about 50km from the Ukrainian border, since the start of the year to protect the southern town and its crucial railway link to Ukraine.

The deployment was triggered by a stray Ukrainian missile that struck the Polish village of Przewodow in the region last November, in an incident that raised fears of the war in Ukraine spilling over the border.

During a visit to Zamosc in July, German Defence Minister Boris Pistorius had not immediately responded to a request by his Polish counterpart to extend the Patriot mission.

Relations between Berlin and the ruling nationalist Law and Justice (PiS) party in Warsaw have been strained, with both sides at odds over a range of topics - from arms deliveries to Kyiv to an EU migration deal rejected by Poland.

Ground-based air defence systems such as Raytheon's Patriot are built to intercept incoming missiles.

They are, however, in short supply across NATO since many allies scaled down the number of air defence units after the Cold War.

Russia's invasion of Ukraine sent NATO allies scrambling to plug the gaps in their own inventories, while also supplying Kyiv with air defence systems to ward off Russian attacks.