A radical Islamist group has come to the fore in the wake of the widespread violence in Egypt.

The group has vowed to amass arms and ammunition to take on the powerful army over president Mohamed Morsi's ouster.

The group which calls itself Ansar al-Shariah has declared its determination to recapture power from the Egyptian military and introduce a stricter form of Islamic Shariah law.

The outfit said Morsi's ouster is tantamount to "a war declared against Islam in Egypt".

Pointing fingers at the liberals, "criminal" secularists and Egyptian Coptic Christians for the recent turmoil, it said the army would turn Egypt into a "crusader [and] secular freak".

The apparently extremist group added that it would collect weapons and train Muslims to "deter the attackers, preserve the religion and empower the Shariah of the Lord".

The group's statement has been posted in cyberspace, according to the SITE Monitoring Service, which keeps track of terrorist outfits' online activities.

The announcement, coming amid a volatile atmosphere in Egypt and incidents of gunfights, is bound to worsen the situation in the troubled nation, according to analysts.