* Police fire teargas during sixth day of protests
* Rare for elite to question president's actions
* Rights groups say at least 50 killed in protests
Islamists and members of Sudan's ruling party called on President Omar Hassan al-Bashir on Saturday to cancel deeply unpopular austerity measures, the first sign of dissent inside ruling circles after a week of unrest that has killed dozens.
Police fired teargas to break up thousands of people in the capital during a sixth day of protests against cuts to subsidies on cooking oil and fuel that doubled pump prices overnight.
Some in the crowd chanted "Freedom, Freedom" and "Bashir, you are a killer", said witnesses.
"Mr President, in the light what is happening we demand an immediate stop of the economic measures," read a petition signed by 31 members of the quasi-official Islamist Movement and the ruling National Congress Party (NCP).
Bashir has ruled Sudan since coming to power in a bloodless 1989 coup that was backed by Islamists and the country's powerful army. It is highly unusual for members of the political elite to question his actions publicly.
"The government has not allowed citizens to demonstrate peacefully," the petition added, urging prosecution for those responsible for opening fire on protesters and compensation for relatives of killed people.
The government has not acknowledged using live ammunition. Police said on Saturday unknown gunmen opened fire on a group of protesters on Friday, killing four people and bringing the official death toll to 33.
There was no immediate reaction to the petition from the government.
Bashir has not commented on the protests since announcing the lifting of subsidies on Sunday - part of austerity measures driven by a severe financial crunch exacerbated by the secession of oil-producing South Sudan in 2011.
The petition was signed by former NCP parliamentary caucus head Ghazi Salah el-Din and a prominent army officer who authorities accused of being involved in a coup attempt against Bashir last year.
ARMED MEN PATROL STREETS
In Khartoum's Burri district, home to a top government official, more than 1,000 people gathered for the funeral of one of the victims, Salah Mudahir Sanhuri, a member of a prominent merchant family with good relations with the government.
The crowd grew to more than 3,000 people, most of whom rushed home when police started firing teargas.
The country's borderlands have grappled with revolts for decades but the relatively wealthy heartland has seen little turmoil in the recent past.
Khartoum has been brimming for days with armed civilians and security personnel carrying rifles, patrolling streets in broad daylight and manning rooftops. Opposition activists have accused the ruling NCP of vandalism and of arming militias to turn the public against the protesters.
The protests are much larger than demonstrations against corruption, rising inflation and early fuel subsidy cuts last year. But they are still tiny compared to the masses who turned out to oust rulers in Egypt and Tunisia.
The United Arab Emirates condemned the crackdown, the first Arab country to criticise Khartoum.
"The UAE expresses its utmost concern at the unexplained and excessive use of force ... and the effects this will have on Sudanese society," Anwar Gergash, minister of state for foreign affairs, told state news agency WAM, calling on Sudan to exercise "wisdom and caution".
The comments come a day after Sudan closed the offices of two UAE-based pan-Arab TV stations, al-Arabiya and Sky News Arabia, for their coverage of protests.
Bashir has stayed in power despite rebellions, U.S. trade sanctions, an economic crisis, an attempted coup last year and an indictment from the International Criminal Court on charges of masterminding war crimes in the western region of Darfur.
He denies those charges and still enjoys the support of the army, his ruling party and many businessmen.
Analysts say Sudan has not seen an Arab Spring-style revolt because of a weak and divided opposition.
Amnesty International and the New York-based African Center for Justice and Peace Studies said at least 50 people had been killed by gunshots to the chest or head by Thursday night, citing witnesses, relatives, doctors and journalists.