Updated

The Egyptian military on Monday assumed joint responsibility with the police for security and protecting state institutions until the results of a Dec. 15 constitutional referendum are announced.

The army took up the task in line with a decree issued Sunday by President Mohammed Morsi. The Islamist leader on Monday also suspended a series of tax hikes announced the previous day on alcohol, cigarettes and other items.

The presidential edict orders the military and police to jointly maintain security in the run-up to Saturday's vote on the disputed charter, which was hurriedly approved last month by a panel dominated by the president's Islamist allies despite a boycott of the committee's liberal, secular and Christian members.

The decree also grants the military the right to arrest civilians, but presidential spokesman Yasser Ali said it was nowhere near a declaration of martial law.

"It is merely a measure to extend legal cover for the armed forces while they are used to maintain security," Ali told The Associated Press.

There were no signs of a beefed up military presence outside the presidential palace, the site of fierce street clashes last week, or elsewhere in the capital on Monday.

Still, Morsi's decision to lean on the military to safeguard the vote is widely seen as evidence of just how jittery the government is about the referendum on the draft constitution, which has been at the heart of days of dueling protests by the opposition and Morsi's Muslim Brotherhood backers. The two sides clashed in Cairo last week, leaving at least six people dead and hundreds wounded in the worst violence of the crisis.

Both the opposition and Morsi's supporters have called for mass rallies on Tuesday.

The opposition has rejected the referendum, but has yet to call for a boycott or instead a "no" vote at the polls.

"A decision on whether we call for a boycott of the referendum or campaign for a `no' vote remains under discussion," Hossam Moanis, a spokesman for the National Salvation Front grouping opposition parties and groups told the AP on Monday. "For now, we reject the referendum as part of our rejection of the draft constitution."

The military last week sent out several tanks and armored vehicles in the vicinity of the presidential palace in Cairo following protests there by tens of thousands of Morsi's critics. It was the first high-profile deployment by the military since it handed power in June to Morsi, Egypt's first freely elected president.

Morsi on Saturday rescinded decrees issued Nov. 22 granting him near absolute powers and placing him above any oversight, including by the courts. He has, however, insisted that the referendum will go ahead on schedule.

Judges have gone on strike to protest Morsi's perceived "assault" on the judiciary and have said they would not oversee the Dec. 15 vote as is customary for judges in Egypt. Judges of the nation's administrative courts announced Monday they were conditionally lifting their boycott of the vote, but they said their supervision of the process was conditional on bringing an end to the siege of the Supreme Constitutional Court by Morsi's supporters.

In exchange for their supervision, they also demanded assurances that authorities would crack down on vote canvassing outside polling stations and offer life insurance policies to the judges.

Morsi's deputy, Mahmoud Mekki, has said the vote could be staggered over several days if there were not enough judges to oversee the referendum.

The court was widely expected to dissolve the panel that drafted the constitution in a session scheduled for Dec. 2. The siege of the Nile-side building in Cairo's Maadi district began Dec. 1.

In a surprise move, Morsi on Monday rescinded a series of decrees issued the previous day to raise taxes on a wide range of items and services, including alcohol, cigarettes, mobile phones, services offered by hotels and bank loans.

The state-owned daily Al-Ahram said the Sunday decrees to raise taxes were issued by Morsi. On Monday, the official MENA news agency carried a statement from Morsi's office saying the president has decided to "suspend" the tax increases.

"The president does accept that citizens shoulder any additional burdens except by choice," the statement said. Morsi, it added, has ordered a public debate on the increases to gauge popular reaction.

"The people will always have the loudest voice and final decision," it added.

It was not immediately clear why Morsi changed his mind about the tax hikes in a matter of hours, but the about-face appeared to have more to do with inexperience rather than a bid by the president to appear sympathetic with the majority of Egyptians who struggle daily to make end meet as the economy's woes deepen. A popular backlash against tax hikes could hurt the chances of the Morsi-backed draft constitution being ratified in the referendum.

Egypt and the IMF last month have reached an initial agreement for a $4.8 billion loan to revive the country's ailing economy. The deal, agreed after nearly three weeks of negotiations in Cairo, will support the government's economic program for 22 months, the IMF said in a statement.

Egyptian authorities said at the time that it intended to raise revenues through tax reform, using the resources generated from new taxes to boost social spending and investment in new infrastructure.