KARACHI, Pakistan -- Gunmen attacked a bus carrying factory workers Wednesday, killing at least 18 people and wounding 10 in renewed ethnic violence in southern Sind province, police and hospital sources said.
More than 350 people have died and hundreds more wounded in Sind's two largest cities of Karachi and Hyderabad in the past two weeks in communal clashes and sniper attacks mostly involving the native Sindhis and Mohajir migrants from India.
The latest incident follows three days of relative calm in the province and comes as an all-party conference called by Sind Chief Minister Aftab Shaban Mirani opened in Karachi to find a solution to the trouble.
Leaders of the Mohajir Quami Movement, a major opposition party representing the Mohajir community, boycotted the conference, contending the meeting could achieve no positive results.
Police said unidentified gunmen opened fire on a bus carrying about 50 employees of a cement factory as it stopped at a railway crossing about 18 miles northeast of the southern port of Karachi at about 12:30 p.m.
Hospital sources said 18 people were killed and 10 wounded.
Police said the passengers were Mohajirs and they believed the attack was ethnic-related.
The cement factory was owned by Mohsin Siddique, an independent member of the Senate who was killed by a sniper in Karachi last week.
There were no immediate reports the bus attack had sparked further unrest elsewhere in the province.
Several areas of Karachi and Hyderabad, 150 miles to the northeast, are under curfew and thousands of troops, police and paramilitary personnel are stationad at key points in the cities.
More than 1,000 people have died in communal clashes in Sind in the past few years. The situation has been aggravated by the easy availability of automatic weapons because of the 12-year-old war in neighboring Afghanistan.
The Sindhis believe they are being made a minority in Sind by natives of other provinces and by the Mohajirs, who came to Pakistan from India following the partition of the subcontinent in 1947.
The Mohajirs, who form 40 percent of the population of Karachi, Pakistan's largest city, feel are discriminated against by the other ethnic groups.