Austrian Chancellor Sebastian Kurz is battling to shore up his coalition government after a video scandal forced the resignation of his far-right deputy Heinz-Christian Strache.
Attention is now focused on Interior Minister Herbert Kickl, a member of Mr Strache’s Freedom Party (FPÖ).
In a brief press statement, Mr Kurz did not confirm speculation that Mr Kickl would be sacked over the affair.
Undercover video showed Mr Strache discussing a deal with a Russian woman.
The scandal erupted on Friday, when the footage from 2017 was published in German media. The next day Mr Strache resigned and Chancellor Kurz – head of the centre-right People’s Party (ÖVP) – said new elections would have to be held.
The video showed Mr Strache and another FPÖ official proposing to offer government contracts to a supposed Russian oligarch’s daughter. They also suggested taking over Austria’s best-selling newspaper, Kronen Zeitung, to turn it into a party propaganda organ.
Russia has denied any involvement. President Vladimir Putin’s spokesman, Dmitry Peskov, said “this is an incident that has not, and could not, have anything to do with us”.
The scandal comes at a particularly awkward time for the FPÖ. Voters across the EU go to the polls on 23-26 May, in European Parliament elections widely expected to boost the numbers of far-right MEPs.
Mr Strache blamed his actions on alcohol and acting like a “teenager”, saying his behaviour had been “stupid” and “irresponsible”, and that he was leaving to avoid further damage to the government.
Mr Kurz is due to meet Interior Minister Kickl soon – but the FPÖ has warned that, if Mr Kickl is forced out, the rest of the FPÖ ministers will quit.
Mr Kickl said “today I have another meeting with Chancellor Kurz, and I will once again make it clear to him that what matters to me is the whole of Austria, the whole of my people, not my position”.
Austrian President Alexander van der Bellen called for early elections to be held in September.
Chancellor Kurz said his party was “shocked” by Mr Strache’s behaviour, which he called “a wrong approach to politics”.
The scandal had damaged Austria’s international reputation, Mr Kurz said.
He demanded a full investigation, saying the video might have criminal ramifications. “Anything illegal must be clarified,” he said.Poll: Pro-, anti-Brexit parties neck-in-neck in EU election