Sudanese women arrested 'for wearing trousers' released
Morality police raided the gathering near the Sudanese capital Khartoum, however, the charges of indecency have now been dropped.
If convicted, the women could have faced 40 lashes and a fine for the provocative "obscene" outfits.
Traditionally, women in Sudan wear loose flowing robes, however, activists warn that the laws are applied arbitrarily and say every year tens of thousands of women are arrested and flogged for indecency.
"The party took place in a closed hall in a building in El Mamoura," campaigner Amira Osman said, adding that the arrest violated women’s rights.
"The girls were arrested for wearing trousers, despite obtaining a permit from the authorities."
Article 152 of the Criminal Code describes indecent acts in public as wearing an "obscene outfit" or "causing an annoyance to public feelings".
Sudanese women risk arrest if police officers deem their clothes to be "provocative".
Women and girls are frequently subjected to harassment under the Public Order Act.
Human Rights Watch documented more than a dozen cases in which security officials raped or threatened to sexually assault women activists, often in the context of arbitrary detention. The women were often warned not to speak of the abuse; some have fled the country.
"They said, 'you women activists and party members, you are all sharmuta [whores],'" recalled one activist, who was arrested in April 2015, on her way to distribute pamphlets urging voters to boycott elections.
Earlier in the year, the national security and intelligence service (NISS) banned an event organised by the "No to Oppression of Women Initiative" without providing a justification.