* Seventh day of unrest
Demonstrations about poor government services
* Prime minister pledges support (Updates wounded toll, adds new protests)
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, wounding six people on Sunday in a week of unrest that has swept southern cities over poor services, police sources said.
"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.
Security forces also faced demonstrations about four km from Eni's Zubair oil field near Basra, a crumbling oil-exporting city. Nineteen people were wounded, three by live fire, according to police sources.
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
The mounting anger comes at a sensitive time. Iraqi politicians are trying to form a government following a May 12 parliamentary election tainted by allegations of fraud.
Prime Minister Haider al-Abadi, who is heading a fragile caretaker government until a new one can be formed, has announced that his government would release funds to Basra for water, electricity and health services.
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, Iraq's Shi'ite heartland.
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 in response to the unrest.
Internet access in Iraq has been dramatically reduced.
Abadi's 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.
Iraq's top Shi'ite cleric, Grand Ayatollah Ali al-Sistani, had 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.
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 Iraq's electorate. (Reporting by Aref Mohammed; Writing by Michael Georgy; Editing by Keith Weir)