Egyptian billionaire Naguib Sawiris filed a lawsuit on Monday against Essam Khalil, the leader of Free Egyptians Party, after Khalil expelled the business tycoon, one of the party’s co-founders.

“The party’s leader and his supporters committed several violations and took several illegal decisions that violate clearly the basic bylaws of the Free Egyptians Party,” Sawiris said in a statement issued on Monday.

The party decided to expel Sawiris last week after he failed to attend a meeting to investigate internal strife in the party.

Until his expulsion, Sawiris had sat on the board of trustees of the party he co-founded in 2011.

Cracks began to show in unity of the liberal party in December when its annual general assembly, in the absence of Sawiris, voted to eliminate the board of trustees, among other changes to the bylaws.

Sawiris responded with threats to take the issue to court, and called for new elections to replace Khalil, who was elected head of the party in 2015.

The Free Egyptians Party is the largest political party in the 596-member House of Representatives, with a total of 65 seats.