LAHORE, Pakistan (AP) — Thirteen people have died in a main Pakistani city after drinking cough syrup suspected of being toxic, police said today.

The victims were all drug addicts who apparently drank the cough syrup in an attempt to get high, said police officer Multan Khan.

Khan said they died at various hospitals in the eastern city of Lahore over the past three days. Five other addicts who drank the cough syrup were being treated.

Police arrested the owners of three drug stores where the cough syrup was sold and sent a sample to determine whether it was toxic, said Khan.

Elsewhere in the country, a bomb hidden in a cement construction block exploded in the southern city of Karachi killing one person, said senior police officer Farooq Awan. Four other people were wounded, he said.

The bomb contained about 1 kilogramme (2.2 pounds) of explosives and was detonated by a mobile phone, said Awan.

Pakistan suspended mobile phone service throughout most of the country on Saturday and Sunday to prevent attacks against Shiite Muslims during a major religious commemoration.

Despite the ban, a pair of bombings over the weekend killed at least 13 people.