BEIRUT (AP) — Iraqi security forces deployed on the streets of the Shiite holy city of Najaf on Saturday after a day of angry demonstrations over failing public services and high unemployment.

Protesters chanting against politicians on Friday attacked the ruling Dawa party's office downtown and stormed the airport outside Najaf, forcing it to shut down.

Calm returned to the city on Saturday, but security apparatuses remained on high alert after demonstrations spread across the country's predominantly-Shiite south.

Rumors circulated on social media on Saturday that the government had shut down the internet in Baghdad, Najaf, and Basra, Iraq's premier oil city and the site of the first protests against joblessness and neglect. Communications links appeared severely limited in the three cities.

Basra, despite producing most of Iraq's oil, is plagued by crumbling infrastructure and widespread poverty. The city suffers from rolling blackouts and water cuts that are felt acutely in the summer months, where temperatures regularly approach 50 degrees Celsius (122 degrees Fahrenheit).

Police confronted protesters gathering near an oil field operated by the Russian company Lukoil, north of Basra, earlier this week, firing their weapons to disperse the crowds.

Other parts of the south depend on agriculture for income, but Baghdad officials, citing water scarcity, issued a ban on planting summer crops, such as rice and corn, angering farmers last month.

The demonstrations were given a boost Friday after a representative of the Shiite community's spiritual leader, the Grand Ayatollah Ali al-Sistani, offered his solidarity in a nationally televised sermon.

"The dear governorate of Basra is the number one in providing the country with financial revenue. And it is the number one in the number of martyrs and those who have been wounded in the fight against the Islamic State group terrorists," said Sheikh Abdul Mahdi al-Karbalai.

"So it is not fair, indeed it is not acceptable, that this governorate is one of Iraq's poorest."

Caretaker Prime Minister Haidar al-Abadi flew to Basra from a defense summit in Brussels on Friday to try to diffuse the unrest. He asked the Basra Oil Company to provide more jobs to locals.

"We applaud each Basrawi who demands his rights," said al-Abadi in a press conference.

At the same time, his office released statements condemning what it called vandalism by "infiltrators" among the demonstrations.

Iraq held national elections in May, but government formation has been stalled by allegations of fraud and the failure of any coalition to secure an outright majority in the new Parliament. It could take weeks or longer for MPs to name a new Prime Minister as the country waits for officials to complete a partial recount.

In Najaf, airport official Fuad al-Gharrawi said Iraq's second busiest airport was operational again. He blamed vandals for damage to the passenger terminal.

Iraq is OPEC's third largest oil producer and home to some of the world's largest oil reserves.