Berlin, Feb 19, 2023 (AFP) - The German FA (DFB) said Sunday Bayern Munich coach Julian Nagelsmann is under investigation over his furious rant at match officials following his side's 3-2 defeat by Borussia Monchengladbach.

The Bayern coach will be asked to provide a statement on Saturday's incident at the beginning of next week, the DFB's investigatory body told AFP affiliate SID.

Nagelsmann apologised on Saturday for storming into the referees' changing room following the defeat in Moenchengladbach.

Aggrieved by a contentious red card decision against Dayot Upamecano which reduced Bayern to ten men early in the game, Nagelsmann reportedly used heated language as he confronted referee Tobias Welz.

Journalists outside heard Nagelsmann say "that's a joke, they're taking the piss", leaving the room calling the officials "spineless".

The Bayern boss later admitted he had "gone too far", but insisted the red card was unfair.

Welz, meanwhile, defended his decision on Sport1 on Sunday morning, and said there was no bad blood between him and Nagelsmann.

"It was an emotional discussion, but there were no insults traded," he said.

The defeat could see Union Berlin move to the top of the table, two points ahead of Bayern, if they beat bottom side Schalke 04 later on Sunday.

Bayern host Union next Sunday.