(CNN) -

Ghana's World Cup challenge is in danger of imploding after two of its star players were thrown out of their squad following allegations of physical and verbal attacks within the team's camp.

Sulley Muntari and Kevin-Prince Boateng were both suspended indefinitely by the Ghana Football Association just a day after the players had finally settled a row over appearance fees.

Muntari, who plays his football with Italian side AC Milan, was accused of launching an "unprovoked physical attack" on Moses Armah -- a member of the GFA, in a statement on their website.

The incident, which took place on Tuesday according to the GFA, has led to Muntari's expulsion from the camp.

He is joined by Milan teammate Boateng, who the GFA says launched "vulgar verbal insults" at coach Kwesi Appiah during training this week.

"Boateng has since showed no remorse for his actions which has resulted in the decision," added the GFA statement.

Boateng told CNN's Chris Eldergill that he had been suspended, but dismissed reports of a fight with Muntari, who was not immediately available for comment.

In an interview with German magazine, Sport-Bild, Boateng says he "absolutely accepts" his punishment and blamed a training ground bust-up for his exclusion.

"Sulley Muntari and I were just joking around, and the coach stopped the session and sent us back to the changing room," said Boateng.

"Afterwards I went to him and asked what he had against me and he started yelling. He insulted me."

"No-one should think I insulted the coach. I'm traveling now, and I wish my colleagues all the best for the match against Portugal," added Boateng, referring to Ghana's final World Cup Group G match Thursday.

Ghana's campaign had already been blighted by controversy over the payment of appearance fees to players.

Following a standoff between players and the GFA, the nation's government was forced to fly $3 million in cash to Brazil to pay players their fees and fend off the prospect of a boycott.

According to coach Appiah, "the practice in Ghana has always been paying the money in cash" as many of the players don't have Ghanian bank accounts.

Deputy Sports Minister Joseph Yamin told Ghanaian radio station Citi FM: "The government mobilized the money and chartered a flight to Brazil."

A statement from the Ghana Football Association said: "The government is pre-financing the payment of the Black Stars appearance fees, which will be reimbursed when FIFA's prize money for Ghana's participation in the World Cup is paid."

Ghana's participation in the World Cup is already under threat with victory against Portugal a must if it is to qualify for the last 16.

The African nation, which reached the quarterfinals four years ago, must defeat Portugal and hope the U.S. fails to gain a result against Germany, though Boateng had already been ruled out of Thursday's game having been sent off in Ghana's 2-2 draw against Germany Saturday.

The news will be of great encouragement to the U.S. which sits second in the group following an opening victory over Ghana and a 2-2 draw with Portugal.

Jurgen Klinsmann's team takes on the Germans in Recife Thursday needing just a point to qualify for the last 16.

But fans hoping to access the stadium were facing a challenge with rainfall causing chaos around the city.

CNN's Fred Pleitgen, who is in Recife, says roads are flooded and traffic is chaotic.