Budapest slammed the European Commission on Thursday after it decided to withhold grants from Hungarian universities as "unacceptable and intolerable" in the latest spat between the two sides. 

Last month, the Commission said that 21 Hungarian universities will no longer be eligible for the bloc's Erasmus grant funding that allows students to spend terms at partner institutions abroad. 

According to the Commission, the universities could also not be eligible to apply for funding for the bloc's Horizon Europe research exchange programs. 

The decision is part of freezing EU funds for Hungary over alleged "corruption" concerns. "What the European Commission is doing with Hungary is unacceptable and intolerable," Prime Minister Viktor Orban's chief-of-staff Gergely Gulyas told reporters.

He added that Budapest was open to making legislative changes to exclude politicians from the foundation boards if requested to do so by the Commission.

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Orban's ruling party officials from Fidesz, including government ministers and state secretaries, currently sit on foundation-run university boards. 

"We do have concerns when it comes to the new legislation introduced by Hungary on November 1... which essentially facilitates the involvement of senior level political executives in the boards of public interest trusts," Commission Spokesperson Balazs Ujvari said in Brussels. 

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Orban's chief-of-staff stressed that if a compromise is not reached by March, the government will fund next year's Erasmus grants estimated at 12.5 million euros ($13.5 million) from the state budget.

He also added Hungary was willing to take the case to the European Court of Justice if the Commission insists on the blockage.