and religious leaders spent Monday locked down in crisis talks, amid fears of widespread sectarian unrest, threatening an already fragile transition from the rule of president Hosni Mubarak.

Coptic demonstrators had taken to the streets on Sunday to denounce an earlier attack on a church in the southern city of Aswan, before the protest degenerated into violence.

State television accused the Coptic demonstrators of firing shots that killed three army troops, prompting fights between Christians and Muslims later that night.

But furious Copts said the security forces attacked the demonstrators, driving vehicles into the crowd and crushing several protesters.

New York-based rights group Human Rights Watch has called for a "prompt, thorough, and impartial" investigation, which "should specifically address the killing of at least 17 Coptic Christian demonstrators who appear to have been run over by military vehicles."

"It should also examine the role of the military and police officers in the violence," HRW said in a statement.

Thousands of people attended a service at the Coptic cathedral in Cairo late on Monday for the funerals of 17 demonstrators.

Live television showed the coffins being brought in a procession from the Copt hospital in downtown Cairo where autopsies were carried out.

The coffins, each bearing the victim's name and flowers arranged in a cross, were lined up in the cathedral for the funeral service before being taken out for burial.

Earlier on Monday, hundreds had gathered outside the Coptic Hospital, chanting against the military council and its head Field Marshal Hussein Tantawi, who took power when Mubarak was ousted in February.

"SOS: Copts under attack from the army of Egypt," read one banner.

Copts complain of systematic discrimination, but since Mubarak's fall, tensions have also mounted between the military -- initially hailed for not siding with Mubarak -- and groups which spearheaded the revolt.

Military prosecutors began questioning 25 people accused of involvement in the clashes.

Egypt's Coptic Orthodox Church led by Pope Shenuda III accused "infiltrators" of triggering the street battle on the Nile waterfront.

Grand Imam Ahmed al-Tayyeb, the country's top Muslim official who chaired a meeting of religious leaders, urged the cabinet to swiftly issue a unified law on building worship places, in a bid to ease sectarian tension.

The cabinet vowed on Monday to look into amending religious laws which would give Copts more guarantees to freedom of worship.

But after months of tensions, unrest and clashes, some say the measure is too little too late.

On Tuesday, leading independent daily Al-Masry Al-Youm called for the resignation of the prime minister in a front page editorial. Continued...