Libyan authorities have banned the formation of political parties based on religious principles ahead of elections scheduled to take place in June.
Parties based on faith, tribe or ethnicity will not be eligible to take part, a government spokesman said.
The National Transitional Council said the law, passed on Tuesday, was designed to preserve "national unity".
But analysts say it is likely to infuriate religious parties such as the Muslim Brotherhood.
"Parties are not allowed to be based on religion or ethnicity or tribe," National Transitional Council spokesman Mohammed al-Harizy told Reuters.