Italy's prime minister Giuseppe Conte has stood by Matteo Salvini's League party amid accusations it sought illicit funds from Russia.
Conte told the Senate that he still had trust in the political movement, which is in a ruling coalition with left-leaning Five Star Movement (M5S).
Italian magistrates said earlier this month they had opened an investigation into possible international corruption following media reports the League had sought millions of euros via a secret Russian oil deal.
Salvini was not there to witness Conte's defence on Wednesday and his absence provoked a protest by M5S senators, who walked out of the chamber.
"Why aren't we in the chamber? Because Salvini should be in there," said Stefano Patuanelli, M5S Senate leader.
It highlights tensions within the ruling coalition, especially around the controversial Turin to Lyon high-speed railway, which Conte has backed on behalf of the government and M5S oppose.
"There are no elements at this stage that could reduce the trust I have in all members of the government," Conte said.
The probe by magistrates began after a leaked transcript of a private meeting between Russian officials and Gianluca Savoini, Salvini's close aide, that was published by BuzzFeed News.
The meeting allegedly took place on October 18, 2018, at the Metropol hotel in Moscow. Both Sovoini and Salvini denied the allegations, saying no such meeting had taken place.