* PM Abadi puts security forces on alert in southern Iraq
* Protesters angry over poor public services, corruption
* Seven protesters hurt in oil city of Basra (Recasts with storming of building, other details)
BAGHDAD, July 14 (Reuters) - Protesters stormed the provincial government building in the Iraqi city of Kerbala on Saturday as protests over poor public services and corruption across southern Iraq entered their sixth day.
Demonstrations also took place in the cities of Najaf and Basra, where security forces announced city-wide curfews amid reports of skirmishes between protesters and local militia groups.
In Basra, seven protesters were injured after clashing with guards belonging to a local militia group, security forces said.
Oil exports from Basra account for more than 95 percent of OPEC producer Iraq's state revenues. Any potential disruptions could severely impact Iraq's limping economy, though officials said the protests had not so far impacted crude production.
Prime Minister Haider al-Abadi announced that his government would release funds to Basra for water, electricity and health services, state television said.
Earlier, Abadi, who also serves as commander-in-chief of Iraq's armed forces, had issued a nationwide order placing security forces on high alert in the southern provinces in response to the protests.
Reinforcement troops from both the Counter-Terrorism Service and the Army's Ninth Division have already been dispatched to Basra to help protect the province's oil fields, security sources said.
Abadi's directive aims to stem the burgeoning protests, which on Friday spread from Basra - where residents had blocked access to the nearby commodities port of Umm Qasr - to the cities of Amara, Nasiriya and the Shi'ite holy city of Najaf.
Hundreds of Iraqis stormed the airport and halted air traffic in Najaf on Friday.
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" such as electricity in the suffocating summer heat.
Sistani, who has millions of followers, rarely intervenes in politics, but has wide sway over public opinion.
Dozens of protesters demonstrated on Saturday at the Safwan border crossing with Kuwait as well as at the entrance to the Majnoon oil field, one of the largest in the country which lies 40 km (25 miles) north of Basra, local security sources said. However, they did not enter the facility.
Iraqi politicians face growing unrest as they try to form a coalition government after a May 12 parliamentary election tainted by allegations of fraud.
Abadi is heading a fragile caretaker government, in place until the new government is formed.
A political bloc led by cleric Moqtada al-Sadr won a majority in the poll on an anti-corruption platform which had appeal across Iraq's electorate. ($1 = 1,190.0000 Iraqi dinars) (Reporting by Ahmed Rasheed in Baghdad; additional reporting by Aref Mohammed in Basra; writing by Raya Jalabi; Editing by Kevin Liffey and Gareth Jones)