A bomb hidden in a cemetery in a southern Afghan city exploded Sunday as a police official and his family were visiting the grave of a relative, police said.

The official and his brother were killed and seven other family members were wounded.

No one immediately claimed responsibility for the attack in Lashkar Gah, the capital of Helmand province, but it matched the declared strategy of the Taliban to target government officials and others who align themselves with the government or international forces.

A lawmaker for Helmand province, Abdulwadood Popal, is a brother of the two men killed in the explosion, but he was not there at the time of the blast. The family was visiting the grave of their relative after morning prayers marking the Eid al-Fitr holiday.

The bomb was buried near the grave, said Helmand Deputy Police Chief Ghulam Rabbani. He said one of the men killed was the police chief for Nawa district, just west of Lashkar Gah. Rabbani did not provide the man's name.

Rabbani said he believed the bomber had directly targeted this family, but did not say if it had been remotely detonated or had been triggered by the visitors.

Afghans commonly visit the graves of relatives on holy days to pay their respects. The Eid al-Fitr holiday marks the end of the Muslim holy month of Ramadan, during which Muslims abstain from food and drink during the daylight hours.

In a message ahead of Eid al-Fitr, Taliban leader Mullah Mohammad Omar instructed his fighters once again to avoid killing or wounding Afghan civilians.

"Employ tactics that do not cause harm to the life and property of the common countrymen," he said in an eight-page message released to news organizations last week. The Taliban have said previously, however, that they do not consider those who collaborate with the government to be civilians.

A U.N. report issued earlier this month said 1,145 civilians were killed and 1,954 injured during the first half of the year, most of them by militants.