CAIRO (AP) — Former U.S. President Jimmy Carter’s center said Thursday it will not deploy monitors for Egypt’s contentious constitutional referendum because of the government’s late release of regulations for witnesses.

The decision reflects concerns that the rushed process leading to Saturday’s vote has undermined the legitimacy of the disputed charter backed by President Mohammed Morsi and his Islamist allies.

It also comes as rights groups warn that the breakneck pace of organizing the vote and changes to the procedure for accrediting elections monitors may lead to frauds in the vote.

Egypt was plunged into political crisis three weeks ago when Morsi issued a decree giving himself near-absolute power. The president rescinded the decree in the face of broad criticism and huge street protests, but not before a panel charged with drawing up the country’s constitution pushed through a draft in a marathon Dec. 1 overnight session and the president ordered a referendum two weeks later.

Morsi’s supporters say the constitution will help end the political instability that has gripped Egypt since the March 2011 overthrow of autocratic leader Hosni Mubarak in a popular uprising. His opponents say the process has been rushed, minority concerns have been ignored, and the constitution is full of obscurely worded clauses that could allow Islamists to restrict civil liberties.

Compounding the sense of crisis are huge rival protests that draw tens and sometimes hundreds of thousands. On Dec. 5 pro-Morsi supporters attacked an opposition sit-in outside the presidential palace, leading to street clashes in which at least 10 people were killed and hundreds wounded.

The opposition was torn between whether to boycott the process or campaign for a “No” vote, but on Wednesday the umbrella National Salvation Front called on Egyptians to cast ballots against the document. It has still left open the possibility of a boycott if judges and monitors were absent and if the state doesn’t provide protection to polling stations.

Nobel laureate Mohamed ElBaradei, who leads the Front, tweeted on Wednesday that “insistence on a referendum in an explosive, polarized, chaotic and lawless environment is leading country to the brink.” The Front has turned down several offers by Morsi to hold talks, saying he has not lived to his promises he made during election campaign, and that he must first delay the vote.

The polarization has hit government bodies and other state institutions.

A large number of judges have been on strike since Morsi’s original decree three weeks ago and most of them will refrain from overseeing the constitution referendum, according to the powerful Judges’ Club that acts as a judges’ union. Egyptian elections law requires judicial oversight of the voting process.

Morsi has responded to the shortage of judges by breaking the vote into two rounds — one on Saturday and another on Dec. 22. The country’s Election Committee says there are 7,000 judges ready to oversee the first round of voting, which will include the provinces of Cairo and Alexandria, the country’s two largest.

Meanwhile, the Carter Center — which monitored Egypt’s past parliamentary and presidential elections — said that it would not be able to conduct “a comprehensive assessment of all aspects of the referendum process.”

Also Thursday, 20 Egyptian rights groups issued a joint statement warning of possible election fraud, and expressing concern that a state-run human rights council has taken charge of issuing monitoring permits, which in the past were obtained directly from the elections committee. The council is headed by Judge Hossam el-Ghariyani, also the head of the controversial constitutional drafting panel.

“The undersigned organizations are deeply concerned about the potential of rigging during or after the referendum,” said the statement. “The undersigned organizations warn that the climate in which the referendum is being conducted does not bode well for a fair voting process,” the statement said.

Copyright 2012 The Associated Press.