A U.S.-based rights group is urging the government of Ethiopia to immediately release 17 Muslim leaders jailed as part of a “brutal crackdown”.

Human Rights Watch says the men were among hundreds who were harassed, assaulted and detained during protests at mosques in the capital, Addis Ababa, last month.

HRW says the crackdown followed months of peaceful demonstrations against government interference in religious affairs, including attempts to control Islamic teachings.

It says although most of those protesters have been released, the 17 Muslim leaders have been held for three weeks without charge or access to lawyers.

Ethiopian police have previously blamed the mosque's committee for instigating the unrest and have warned foreign elements against influence that may be fueling the protests.

Human Rights Watch is calling on the Ethiopian government to address the grievances of the Muslim community through dialogue and not violence.

Muslims are Ethiopia's second-largest religious group, making up one-third of the country's 94 million people.

The Ethiopian government has expressed concern about the influence of Salafist, or Wahbist Muslims, who practice a more conservative form of Islam.

To combat this, the government has actively promoted the al-Ahbash sect of Islam, which is based on the teachings of an Ethiopian scholar who had been living in exile in Lebanon.