Former Barcelona coach Quique Setien and three of his assistants announced on Thursday they are suing the club for failing to fulfil the terms of their contracts after being sacked last month.
In a joint statement with assistants Eder Sarabia, Jon Pascua and Fran Soto released on his official Twitter account, Setien said he had only received written notice of the termination of his contract on Sept. 16, having been sacked on August 17.
He said he had not received any compensation from the club a month after being sacked.
Barca declined to comment.
Setien's complaint piled yet more pressure on president Josep Maria Bartomeu less than an hour after a group seeking his removal announced they had gathered enough signatures to force a vote of no-confidence against him.
Setien was appointed Barca coach in January after Ernesto Valverde was dismissed but he was sacked in August after the team ended the season empty handed and lost 8-2 to Bayern Munich in the Champions League quarter-finals, their worst ever defeat in European competition.
"After a month of absolute silence from Barcelona's board of directors, and after diverse demands on our behalf, we did not receive any communication from the club until receiving a letter yesterday via burofax (recorded delivery)," said the statement.
"Said letter revealed the clear intention from the club to not comply with contracts we signed on Jan. 14 2020."
The statement added: "Given everything expressed above, we have felt the need for our lawyers to find a solution to this conflict and take the corresponding legal action, in order to preserve our rights and everything we had previously agreed with Barcelona."
Barcelona president Josep Maria Bartomeu is set to face a vote of no-confidence from the club's members after a campaign group seeking to oust him gathered the necessary number of signatures on Thursday to force the vote.
"Mes que una mocio" (More than a motion), a group of members supported by candidates for next year's presidential election, said they had gathered 20,731 votes by Thursday's deadline.
Barcelona announced later on Thursday that 20,687 signatures backing a vote of no confidence have been counted -- comfortably clearing the required 16,520 to trigger the vote.
"Member Jordi Farre, promoter of the vote of censure against the FC Barcelona board of directors, has delivered the signatures of the club members who support his request to the offices of the Barcelona Supporter Services Office (OAB)," Barcelona said in a statement.
The signatures must now be examined and counted over the next 10 days by a three-person panel comprising of a representative from the club, the Catalan soccer federation and the campaign group proposing the vote of no-confidence.
Provided at least 16,520 votes are valid, the club's statutes state it must hold a referendum within three months, with 66.5% of the club's 150,000 members needing to vote against Bartomeu and his board to force their removal.
Should the motion of censure go ahead, Bartomeu will be the third president to face a vote of no-confidence after Josep Lluis Nunez in 1998 and Joan Laporta in 2008, with the vote failing to pass on both occasions.
Bartomeu's time as club president is coming to a close regardless of whether the vote goes ahead, as he will be unable to contest the elections that will be held in March after serving two terms.
The motion of censure was filed by presidential candidate Jordi Farre on Aug. 26, the day after captain Lionel Messi had declared his intention to leave the club.
Messi, Barca's all-time top scorer, later announced he is staying at the club for this season as he did not want to face a legal battle with the club.
Resentment against Bartomeu has been growing in the last year due to the club's worsening finances and the team's decline on the pitch, which came to a head with their 8-2 defeat to Bayern Munich in the Champions League quarter-finals in August.
Bartomeu, who became president in 2014 when then incumbent Sandro Rosell resigned, also faced criticism for the 'Barca-gate' scandal after the club hired a social media monitoring firm which was accused of seeking to undermine other presidential candidates as well as former and current players.
Club member Agusti Benedito tried to trigger a vote of no-confidence against Bartomeu in September 2017 but only managed to gather 12,504 votes, 4,000 less than required.