German Chancellor Olaf Scholz has shot down calls on Berlin to send fighter jets to Ukraine as "irrational."

The calls come just days after Germany's U-turn on delivering Leopard 2 tanks to the country defending itself against a Russian invasion.

"It's strange that this debate is being held," he said during a press conference in Santiago de Chile on Sunday evening, while on a four-day trip to South America.

A serious debate was now necessary and not "a bidding competition ... in which perhaps domestic political motives play a bigger role than support for Ukraine," Scholz said.

A debate on an issue as important as arms deliveries had to focus on the matter at hand as well as rational considerations, the German chancellor stressed.

Scholz and U.S. President Joe Biden had ruled out no-fly zones over Ukraine shortly after the beginning of the Russian invasion of its neighbor, Scholz pointed out because that would have lead to a conflict between Russia and NATO.

Likewise, "nonsensical proposals" as the deployment of ground troops had been rejected. "Everything has now been said (on the matter), including by me," Scholz added.

In the debate on no-fly zones over Ukraine last year, Scholz and Biden rejected the idea because NATO would have had to provide its own fighter jets to enforce it.

If Berlin decided to supply Kyiv with fighter jets, however, those would be operated by Ukrainian pilots.

Ukraine has asked its Western allies to send combat aircraft and the U.S. has not ruled out delivery on principle.

The head of Scholz's governing Social Democratic Party (SPD) on Sunday also didn't explicitly rule out supporting Ukraine with fighter jets.

Asked whether she would rule out the delivery of combat aircraft, SPD leader Saskia Esken told German broadcaster ARD that Germany is not a party to the war, and the government wants to "avoid this in the future."

"The decisive factor is that Germany and NATO are not party to this war," which is why the German government is in very close consultation with US counterparts on these issues, said Esken, whose party leads a coalition government under Scholz.

At the same time, it was important for Germany to make it clear to Russian President Vladimir Putin with every decision "that we reject Russian aggression."

The comments come after the German government promised Ukraine a delivery of 14 Leopard 2 tanks from Bundeswehr stocks on Wednesday, after a long period of waiting for a similar commitment from the U.S.