* Seventh day of unrest
Demonstrations about poor government services
* Prime minister pledges support (Updates casualties)
By Aref Mohammed
BASRA, Iraq, July 15 (Reuters) - Iraqi police fired in the air as hundreds of protesters tried to storm the main provincial government building in Basra on Sunday, wounding seven demonstrators, police sources said, in unrest over poor state services that has swept southern cities over the past week.
The mounting anger has put Iraqi Prime Minister Haider al-Abadi in a difficult position. He hopes to serve a second term when politicians form a new government following a May 12 parliamentary election tainted by allegations of fraud.
Troubles in Basra have reinforced the widely-held view that Iraqi leaders rarely deliver on promises of a brighter future.
"Some of the protesters tried to storm the building. We prevented them by using water cannons and tear gas," said one of the police sources.
Nineteen security forces were also wounded in clashes with stone-throwing protesters at the provincial government headquarters.
Iraq's top Shi'ite cleric, Grand Ayatollah Ali al-Sistani, has expressed solidarity with protesters, saying they faced an "extreme lack of public services".
Sistani, who has millions of followers, rarely intervenes in politics, but has wide sway over public opinion.
Security forces also faced demonstrations about four km from Eni's Zubair oil field near Basra, a crumbling oil-exporting city. Nineteen protesters were wounded, three by live fire, according to police sources.
Twenty one members of the security forces were wounded after protesters hurled bricks and stones at them.
Internet access in Iraq has been dramatically reduced.
Local officials said demonstrations have not affected crude production in Basra, whose shipments account for more than 95 percent of OPEC producer Iraq's state revenues.
Any disruption could severely impact the country's limping economy and push up global oil prices.
STRUGGLE TO REBUILD
On Friday, protesters stormed the international airport in the holy city of Najaf, temporarily suspending air traffic.
Jordan's state airline said on Sunday it had suspended four weekly flights to the Iraqi city of Najaf due to the "security situation at its airport, a company statement said. Flyudubai also followed suit.
Abadi has announced that his caretaker government would release funds to Basra for water, electricity and health services.
A political bloc led by populist cleric Moqtada al-Sadr won a majority in the poll on an anti-corruption platform which had appeal across Iraqs electorate.
Substantial relief is unlikely to come anytime soon for Basra, once dubbed the "Venice of the Middle East" for its network of canals resembling the Italian city.
Iraq needs to generate billions of dollars to rebuild after its three-year war with Islamic State.
Demonstrators, who are demanding jobs and better government services, have cut off access to the southern Umm Qasr commodities port.
Security forces have battled protesters in Basra and several other cities in the south.
Saddam Hussein oppressed the country's majority Shi'ites, neglecting their southern heartland.
Successive Shi'ite-led governments that have run the country since he was toppled in 2003 have also done little to improve lives in Basra and others cities in the region, where oil money rarely trickles down to the population.
The demonstrators have taken the unusual step of attacking buildings belonging to powerful Shi'ite militias, in addition to local government headquarters.
Abadi, who also serves as commander-in-chief of Iraq's armed forces, had earlier issued a nationwide order placing security forces on high alert in the southern provinces.
His directive aims to stem the burgeoning protests, which spread from Basra to the cities of Amara, Nasiriya and the Shi'ite holy city of Najaf.
(Reporting by Aref Mohammed in Basra and additional reporting by Suleiman al-Khalidi in Amman; Writing by Michael Georgy; Editing by Keith Weir)