Egypt vowed Saturday to confront the Muslim Brotherhood with "full force" as the Islamists called for further rallies, a day after clashes between protesters and police killed at least 17 people.
The Brotherhood, which demands the reinstatement of ousted president Mohamed Morsi, has organised near-daily protests despite its designation last month as a terrorist organisation.
Friday's violence was the deadliest in almost three months, after Morsi supporters rallied in the thousands in defiance of the interim government's designation of the Brotherhood as a terrorist group last month.
The designation carries harsh prison sentences for members arrested during demonstrations or leaders of the influential Islamist movement.
"The organisation continues its criminal activities despite its designation as a terrorist group," said the government, installed by the military following Morsi's overthrow in July.
The state "will confront the activities of this terrorist group with full force," it said.
Police arrested 258 suspected protesters during the clashes, security officials said.
The crackdown prompted another diplomatic row between Egypt and Qatar, which had supported Morsi and criticised on Friday night Cairo's treatment of the Brotherhood and protesters.
The Egyptian foreign ministry said Saturday it summoned Qatar's ambassador in Cairo in protest at Doha's criticisms, and to object to Qatari broadcaster Al-Jazeera's coverage of the unrest.
Qatar, a main backer of the Muslim Brotherhood in the region, had condemned the organisation's designation as a terrorist group.
The decision was "a precursor to a shoot-to-kill policy against demonstrators," said a foreign ministry statement, published by the official Qatari QNA news agency.
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More than 1,000 people, mostly Islamists, have been killed in street clashes, and thousands have been imprisoned, in the crackdown on Morsi's supporters following his ouster.
The military is also battling an Islamist militant campaign in the Sinai peninsula that has killed scores of soldiers and policemen since Morsi's overthrow in July.
Another soldier was killed Saturday when a road side bomb detonated near his vehicle, the military said.
The Brotherhood was blacklisted as a terrorist group following a suicide car bombing of a police headquarters north of Cairo, which was claimed by a jihadist group in Sinai.
The Brotherhood, which insists it is peaceful, has called for a surge in rallies ahead of the second hearing in Morsi's trial for inciting the killing of protesters during his turbulent year in power.
Morsi, toppled following days of massive rallies demanding his resignation, also faces trial for allegedly colluding with militants to carry out attacks and prison breaks in early 2011.
His Muslim Brotherhood movement won a series of elections following the uprising that overthrow strongman Hosni Mubarak in February 2011.
The government says the Islamists now intend to disrupt a January 14-15 referendum on a new constitution, the first in a series of polls that it says will restore an elected government by the end of the year.
The Islamists, who have called for a boycott of the referendum, are also urging a "million man march" on Wednesday to coincide with the Morsi hearing.
"Continue your days of revolutionary rage and peaceful protest activities," the Brotherhood-led Anti-Coup Alliance said Friday night in making its call.
The crackdown on the group has jailed most of its leaders and severely impaired its ability to organise large numbers of protesters.