CAIRO — A political party led by a prominent Egyptian Islamist said Monday it would boycott this week’s referendum on the country’s new constitution to protest the arrests of people campaigning against it.

The announcement by The Strong Egypt party of Abdel-Moneim Abolfotoh came on the eve of voting on the charter, the first step in a military-backed transition road map put in place after the ouster of Islamist President Mohammed Morsi in a popularly-backed coup last July.

The charter had been drafted in 2012 by an Islamist-dominated panel under Morsi, but was suspended after the coup and heavily amended by two panels under the interim government. While limiting the role of Islamic law in legislation, the charter consolidates military privileges such as the ability to try civilians in front of military tribunals in specific conditions.

The January 14-15 vote provides the country’s increasingly popular military chief, Gen. Abdel-Fattah el-Sissi, with a first electoral test since he ousted Morsi. A comfortable “yes” vote and a respectable turnout would be seen as bestowing legitimacy, while undermining the Islamists’ argument that Morsi remains the nation’s elected president.

To secure the vote from possible disruption, some 350,000 police and army troops including special forces and paratroopers backed by armored vehicles and helicopters are to be deployed in the streets across the country.

Morsi’s Brotherhood, which fell from power and is now branded as a terrorist group, has called for a boycott of the vote as well.

In its latest statement, a Brotherhood-led alliance said: “the blood of Egyptians is not a ladder to take over the seat of the kidnapped President.” Regarding whether to vote “yes” or “no” on the document, it added: “The boycott is the only way.”

Morsi is on trial over several charges, including inciting killing of protesters, conspiring with foreign groups and orchestrating jailbreaks during 2011 uprising which forced his predecessor Hosni Mubarak from power.

“Topple the blood-stained constitution with civilized, peaceful masses,” it said, urging its supporters not to hold demonstrations near polling stations.

Outside Egypt, The Supreme Election Committee said that only 15 percent of more than 680,000 eligible expatriate voters had cast their ballots for the past five days worldwide. It explained that the low turnout is due to cancellation of voting by mail, which was the reason behind high expat turnout in past referendums including one on the 2012 constitution. Participation by Egyptians living abroad in that poll reached nearly 40 percent.

Copyright 2014 The Associated Press.