Libya, preparing for elections in June, issued a new law Wednesday banning parties based on religious principles, the council spokesman said.

The ruling National Transitional Council’s (NTC) unexpected move was criticized by Islamic oriented parties willing to compete in upcoming elections.

National Transitional Council spokesman Mohammed al-Harizy said the council passed the law governing the formation of political parties on Tuesday evening. “Parties are not allowed to be based on religion or ethnicity or tribe,” he told Reuters.

He stressed that the provision was put forward to preserve “national unity”.

The Muslim Brotherhood, Libya’s most organized political movement, denounced the move.

“This is not democracy,” said Mohammed Gaira, spokesman for the Freedom and Development party founded by the Muslim Brotherhood earlier this year.

“We are a nationalist party, and Islam is our religion. This law is unacceptable and only suits liberals he added,” according to Aljazeera.

He said this would spark controversy in Libya, whose population of six million are almost entirely Muslims.

“This kind of clause is only useful in countries where there exists many religions, not in Libya where most people are religious Muslims,” Sawan told Reuters.

Sawan pointed out that if the law was not reviewed he would challenge it.

Libya’s NTC has already stressed that the country will be run in accordance with sharia law, though the exact place of Islamic law in the legal system will be settled only once a new constitution is written after elections, Aljazeera reports.

Political analysts have predicted the Muslim Brotherhood is likely to emerge as Libya’s most influential and organized force.