By Miranda Murray and Andreas Rinke

BERLIN (Reuters) -German Chancellor Friedrich Merz discussed his country's offer to buy Patriot air defence systems for Ukraine with U.S. President Donald Trump by phone on Thursday, according to a government spokesperson.

Merz initiated the call with Trump to promote arms deliveries to Ukraine, particularly Patriots, after the Pentagon paused some shipments, the spokesperson told Reuters on Friday.

Spiegel magazine first reported the phone call.

Germany was in "intensive talks" to buy Patriots for Ukraine to help it counter some of the heaviest Russian attacks since the war began in 2022, the spokesperson said earlier on Friday at a press conference.

"There are various ways to fill this Patriot gap," the spokesperson told journalists, adding that one option being considered was buying the Patriot missile batteries in the United States and then sending them on to Kyiv.

The U.S. has paused shipments of certain critical weapons to Ukraine including 30 Patriot air defence missiles, sources told Reuters this week, due to low stockpiles, prompting warnings by Kyiv this would weaken its ability to defend itself.

Germany has sent three of the U.S.-made systems from its military stocks to Ukraine, and Defence Minister Boris Pistorius last month launched an initiative to chase down more of them at the Ramstein group of some 50 nations.

Pistorius would travel to Washington later this month for talks with his U.S. counterpart about his initiative, as well as production capacities, said a defence ministry spokesperson.

"Of course these issues will also be on the agenda," said the spokesperson.

The U.S. Embassy in Berlin was not immediately available for comment.

Pistorius has floated the idea of buying Patriot systems that could be freed up to bypass long industrial delivery times and ensure they get to Ukraine quickly.

Ukraine is increasingly desperate for the systems that it relies on to destroy fast-moving ballistic missiles, with Ukrainian President Volodymyr Zelenskiy also calling Trump on Friday to discuss air defence weapons and Russian strikes.

Russia pummelled Kyiv with the largest drone attack of the war, injuring at least 23 people, just hours after Trump spoke to Russia's Vladimir Putin on Thursday.

Germany, Ukraine's second largest donor after the United States, has sought to take on more of a leadership role in ensuring backing for Kyiv as U.S. support has been thrown into question under Trump.

While Europe could sustain Ukraine's resistance without U.S. military support, according to a senior German military official, the challenges would be immense.

Germany has provided a total of 38 billion euros ($43 billion) worth of military aid to Ukraine, including funds earmarked for the coming years, according to the defence ministry.

A Bloomberg News report on Friday said Germany was preparing a 25-billion-euro tank order to ramp up its NATO brigades. The defence ministry had no immediate comment.

(Reporting by Ludwig Burger and Miranda Murray, Editing by Friederike Heine, Kirsti Knolle, Matthias Williams, Alexandra Hudson and Alex Richardson)