Afghan officials say two bombings in the west and south of the country have killed at least 18 civilians, including 16 members of a wedding party whose van ran over a roadside bomb.

Officials say the roadside bomb detonated Tuesday in the western province of Herat, destroying the van and killing all but four of the occupants, who were mostly from the same extended family. The dead include 11 children, four women and the driver. There was no immediate claim of responsibility.

In the second attack, a Taliban suicide car bomber blew up his vehicle near a police station in the southern city of Lashkar Gah, the capital of Helmand province. Officials say the blast happened outside a butcher shop that largely served Afghan security personnel. At least two civilians were killed, including a child, and 26 other people were wounded, 10 of them policemen.

NATO forces handed over security control of Lashkar Gah to Afghan authorities in July as part of a transitional process aimed at making it possible for all foreign combat forces to leave Afghanistan by the end of 2014.

In another development, hundreds of protesters rallied in the Afghan capital, Kabul, on Tuesday to call for an international investigation into the assassination of former Afghan president Burhanuddin Rabbani last week.

Mr. Rabbani was leading the Afghan government's peace talks with the Taliban. He was killed at his Kabul home by a suicide bomber pretending to deliver a “message of peace” from Taliban leaders.

Many of Tuesday's demonstrators held signs saying, “Death to the Taliban” and “Death to Pakistan.” Some Afghan officials have said recent assassinations of Afghan officials may have been coordinated in part by Pakistan.

The leader of the protest was former Afghan intelligence chief Amrullah Saleh, who stepped down last year after opposing the government's efforts to talk to the Taliban.