Libya's interim interior minister, Fawzi Abdel-Al, resigned Sunday after his security forces failed to stop violent attacks against Sufi Muslim shrines in the capital city of Tripoli and the western city of Zliten, Reuters reported.

On Friday, a Sufi mosque and adjoining library were vandalized in Zliten. The mosque's dome collapsed and hundreds of books were destroyed.

And, on Saturday, in broad daylight, Salafist activists brought in a bulldozer to flatten the Sidi Al-Sha'ab shrine, which was centuries old and contained 50 graves considered sacred by Sufi Muslims.

The attacks show that post-revolution Libya still faces considerable challenges as it works to cobble together a functional representative government.

Last year's revolution saw the overthrow of dictatorial leader Moammar Gadhafi after an eight-month struggle that cost tens of thousands of lives. Since then, general elections have taken place to institute a transitional government.

That government now struggles to assert control over a country whose sectarian tensions were heightened by competing militias during the violent revolution.

Libya's General National Congress held an emergency meeting Sunday to address the anti-Sufi attacks. Security forces face allegations of standing back while Salafists destroyed the shrines, and Sufis are calling for justice.

"These gangs have so much hatred for our way of life and want to erase us from the Libyan landscape," Sufi university professor Makki Ali told Reuters. "As Sufis, we are scared they will begin a witch-hunt and attack us in our homes if the government doesn't take control of security."

The interim interior minister argued his forces acted to the best of their ability, but he resigned in the face of public and governmental criticism.

"Minister Fawzi Abdel-Al submitted his resignation in protest against the unacceptable words from the National Congress," government aide Ziad Muftah said, according to Reuters. "The resignation has not been accepted by the prime minister's office yet."

Libyan Prime Minister Abdurrahim el-Keib also defended security forces, telling reporters the national security committee "is just a temporary transitional security committee, and we have just come out of a war."

The incidents reflect a trend of sectarian violence that has cropped up across the Middle East in the aftermath of Arab Spring revolutions. Some hardline Islamists, emboldened by successful regime overthrows, have turned their anger toward the Sufi branch of Islam, a mystical sect that many conservative Muslims consider heretical.

The problem is compounded by the fact that post-revolution governments are often weak on security as they work to organize new systems of governance.

Similar incidents of violence against Sufi sites of worship have occurred elsewhere in Libya, as well as Mali and Egypt.