* Blockaded port is lifeline for grain imports
* Ten protesters dead since Monday
* Citywide curfew in place
* Residents say water supply contaminated with salt
* Thousands hospitalised with diarrhoea (Revises death toll)
By Aref Mohammed and Raya Jalabi
BASRA, Iraq, Sept 6 (Reuters) - Hundreds of people took to the streets of Iraq’s southern oil city Basra on Thursday for a fourth day of violent protests, where residents, angry over the neglect of their city’s collapsing infrastructure, set fire to political offices.
Ten demonstrators have been killed in clashes with security forces and dozens injured since a wave of protests began on Monday. Tens of security forces members have also been injured, some by a hand grenade, health and security officials said.
Protesters on Thursday targeted several provincial government buildings, setting the headquarters of the local government on fire, and blocked main roads in the city centre.
A protester died on Thursday night from burns sustained during the torching of the government headquarters, health and security sources said.
People attacked the offices of the state-run Iraqiya TV and set fire to the headquarters of the ruling Dawa Party, the Supreme Islamic Council and the Badr Organization, whose leaders are all vying to form Iraq’s ruling coalition. Two more protesters died during those attacks, local security and health sources said.
Protesters also set fire to the offices of a powerful Shi’ite militia, Asaib Ahl al-Haq, and those of the Hikma Movement about 100 km (60 miles) north of Basra, and stormed the house of the acting head of the provincial council.
The provincial government headquarters was engulfed in flames, local police and military sources said. No protesters were near the building when the fire broke out in the afternoon, they said.
Security forces, including members of the rapid response team, were expected to be patrolling in high numbers on Thursday. By nightfall, however, they were few and far between in the city centre and were not interfering heavily in protesters’ activities.
Basra security officials announced a curfew from 10:30 p.m. (1930 GMT) to help quell the protests. A citywide curfew was originally planned for 3 p.m., but was cancelled minutes before it was due to come into force.
An Iraqi security official in Basra said they were struggling to cope with the demonstrations. “We are still waiting for orders from the state’s highest authorities,” he said.
The port of Umm Qasr, the country’s main seaport and its principal lifeline for grain and other commodity imports, closed on Thursday. Port employees said all operations had ceased after protesters began blocking the entrance, which lies about 60 km (37 miles) from Basra, on Wednesday night. Trucks and staff were unable to get in or out of the complex.
Oil exports, handled at offshore terminals, remained untouched by the unrest. Oil exports from Basra account for more than 95 percent of Iraqi state revenues.
Southern Iraq, heartland of the Shi’ite majority, first erupted in unrest in July as protesters expressed rage over collapsing infrastructure, power cuts and corruption.
Residents in Basra, a city of more than 2 million people, say the water supply has become contaminated with salt.
A Health Ministry spokesman told a news conference in Baghdad that 6,280 people had been recently hospitalised with diarrhoea because of the oversalinated water.
Public anger has grown at a time when politicians are struggling to form a government after an inconclusive parliamentary election in May. Residents of the south complain of decades of neglect in the region that produces the bulk of Iraq’s oil wealth.
Leading political figures, embroiled in government formation negotiations in Baghdad, have scrambled to respond to the crisis, condemning rivals for inaction.
Moqtada al-Sadr, a populist Shi’ite cleric whose electoral bloc came first in May’s election, called for an emergency televised session of parliament to discuss “radical” solutions to the crisis in Basra, a city “without water, electricity or dignity”.
Iraq’s second biggest city, Basra is a stronghold of Sadr, who has recast himself as an anti-corruption campaigner and has allied himself with incumbent Prime Minister Haider al-Abadi.
The prime minister responded that he would be ready to attend a meeting of parliament with the ministers and officials concerned to try to find a resolution.
Abadi has ordered the Interior Ministry to conduct an investigation into the protests and to instruct security forces not to use live ammunition.
Parliament convened for the first time on Monday, but failed to elect a speaker as mandated, delaying its next meeting to Sept. 15.
Reporting by Aref Mohammed in Basra and Raya Jalabi in Erbil; Writing by Raya Jalabi; Editing by Janet Lawrence, Andrew Heavens and Peter Cooney