Egyptian Christians turned their fury against the army on Monday after at least 25 people were killed when troops crushed a protest using tactics that deepened public doubts about the military's ability to steer Egypt peacefully towards democracy.

In the worst violence since Hosni Mubarak was ousted, armoured vehicles sped into a crowd late on Sunday to break up a protest near Cairo's state television. Online videos showed mangled bodies. Activists said corpses were crushed by wheels.

Tension between Muslims and minority Coptic Christians has simmered for years but has worsened since the anti-Mubarak revolt, which gave freer rein to Salafist and other strict Islamist groups that the former president had repressed.

The ruling military council called on the interim government to investigate the clashes urgently and said it would take necessary measures to maintain security, state TV said.

But much of the anger from Sunday's violence targeted the army, accused by politicians from all sides of worsening social tension through a clumsy response to street violence and not giving a clear timetable for handing power to civilians.

'This is a huge crisis that could end in a civil clash. It could end in dire consequences,' presidential hopeful Amr Moussa told a news conference on the violence attended by leading politicians. 'An immediate investigation committee must be formed, with immediate results.'     

Investors, who Egypt is desperate to attract to plug a deep funding shortfall, sold Egyptian shares, pushing the benchmark index down as much as 5.1 percent at the open. The index closed down 2.3 percent.

'One big problem Egypt faces now is that, increasingly, there is no one in power with the authority and credibility to calm the situation down,' said a senior Western diplomat.  'After (Sunday's) events, there is an increasing risk that the military will come into conflict with the people. The authority of the prime minister is dangerously eroded. None of the presidential candidates yet has the standing,' he said.

Christians, who make up 10 percent of Egypt's roughly 80 million people, took to the streets after blaming Muslim radicals for partially demolishing a church in Aswan province last week. They also demanded the sacking of the province's governor for failing to protect the building.

Some of the protesters said agitators, whom they described as thugs, sparked violence that prompted the heavy-handed  military tactics. 'Why didn't they do this with the Salafists or the Muslim Brotherhood when they organise protests? This is not my country any more,' said Alfred Younan, a Copt speaking near Cairo's Coptic Christian hospital where many of the dead were taken.

The violence overshadows Egypt's first parliamentary poll since Mubarak fell. Voting starts on November 28.     

Prime Minister Essam Sharaf, appearing on state TV in the early hours of Monday, said the government's attempts to build a modern, democratic state were being disrupted by security concerns and talk of plots against democracy.

'We will not surrender to these malicious conspiracies and we will not accept reverting back,' he said before the interim cabinet met for an emergency meeting.

The Health Ministry said 24 people were killed and 322 wounded, including more than 250 who were taken to hospital.  State media later put the toll at 25 dead, most of them Copts. - Reuters