The lockdown is the first to disrupt operations in OPEC’s second-largest producer since protests erupted in October.

Iraqi anti-government protesters blockaded an oilfield and rallied in southern cities on Sunday amid political deadlock as political factions remained paralysed in their attempts to form a new cabinet.

Several hundred people demanding jobs shut off access to the Nasiriya field, 300km (190 miles) south of the capital, Baghdad, which produces 82,000 barrels oil per day, executives said.

The two-day blockade is the first to disrupt operations in OPEC’s second-largest producer since the start of the popular revolt set to enter its fourth month in early January.

The youth-led protests demand the removal of the entire political class that has run the country in the aftermath of the 2003 US-led invasion that toppled former President Saddam Hussein.

Demonstrators have vented their fury at what they consider inept politicians who have mismanaged the economy, enriched themselves and are beholden to powerful neighbour Iran.

Sit-in protests have shut down state offices and schools across the Shia-majority south for weeks, and demonstrators again declared a “general strike” in Diwaniya on Sunday, the first day of the working week.

Commenting on the Nasiriya field, the oil ministry said in a statement that the halting of production by protesters would not affect the country’s exports and production operations, adding that Iraq will use the additional output from southern oilfields in Basra to make up for the missing shipments.

The incident marks the first time protesters have shut an entire oilfield, though they have blocked entrances to refineries and ports in the past.

Political deadlock

Protesters have continued to take to the streets despite being met with batons, tear gas and, at times, live rounds in violence that has killed nearly 460 people and injured some 25,000.

The demonstrators achieved a partial success in November with the resignation of Prime Minister Adel Abdul Mahdi, who however remains in charge in a caretaker role.

Pro-Iranian and other political factions have since wrangled over finding a successor – so far without success. And although parliament has just voted for an electoral reform package, there has been no indication that the early polls many citizens are calling for will be held anytime soon.

Heightening the turmoil, President Barham Salih last week threatened to resign rather than put forward the name of a pro-Iran candidate to form the next government.

Nasiriya student demonstrator Osama Ali praised the head of state, saying he had “foiled the attempts by parties and militiamen to kill off the revolution to protect their own interests”.

“This gives us hope to continue our peaceful movement until we obtain all our demands,” he told AFP news agency.

Those demands include an end to a system that doles out state jobs according to ethnicity and religion, and a stop to corruption. The protesters also want justice for those activists who have been murdered, many shot dead in the streets or outside their homes.

Dozens have also reported being abducted to rural areas near Baghdad for several hours or days before being abandoned by the roadside. The United Nations has accused “militias” of waging a sweeping campaign of threats, kidnappings and murders of demonstrators.

The state-run Human Rights Commission says it has still not heard from 56 missing activists.