LAHORE, Pakistan - Thirteen people have died in a main Pakistani city after drinking cough syrup suspected of being toxic, police said Monday.

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 kilogram (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.

Awan, the police officer, said he suspected the bomb in Karachi was meant to target Shiites over the weekend, but militants were not able to detonate it because of the mobile phone ban.

Shiites are currently observing the holy month of Muharram. Pakistani Shiites on Sunday marked Ashoura, the most important day of the month.

Pakistan has a long history of Sunni Muslim extremists targeting Shiites, who they consider heretics.

Also Monday, police in Pakistan's capital, Islamabad, found and defused a bomb planted underneath the car of one of Pakistan's most prominent TV anchors, Hamid Mir of Geo Television.

The bomb was made up of half a kilogram (1 pound) of explosives stuffed in a tin can, said Islamabad police chief Bani Amin. It was placed in a bag and attached to the bottom of Mir's car, said Amin.

One of Mir's neighbours noticed the bomb underneath the car after the TV anchor returned from a local market, and the police were notified, said Rana Jawad, a senior official at Geo TV.

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Associated Press writers Adil Jawad in Karachi, Pakistan, and Zarar Khan in Islamabad contributed to this report.

Earlier on HuffPost:

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  • Pakistani Army soldiers stand at the site of a car bomb explosion, in the Pakistani town of Darra Adam Khel in the troubled Khyber Pakhtunkhwa province bordering Afghanistan, Saturday, Oct. 13, 2012. (AP Photo/Mohammad Sajjad)

  • Pakistanis check the damage caused by a car bomb explosion, in the Pakistani town of Darra Adam Khel in the troubled Khyber Pakhtunkhwa province bordering Afghanistan, Saturday, Oct. 13, 2012. (AP Photo/Mohammad Sajjad)

  • Seen through the wreckage of a vehicle, Pakistani Army soldiers check the site of a car bomb explosion in the Pakistani town of Darra Adam Khel in the troubled Khyber Pakhtunkhwa province bordering Afghanistan, Saturday, Oct. 13, 2012. (AP Photo/Mohammad Sajjad)

  • A Pakistani youth sits amid the rubble of offices destroyed in a car bomb explosion in the Pakistani town of Darra Adam Khel in the troubled Khyber Pakhtunkhwa province bordering Afghanistan, Saturday, Oct. 13, 2012. (AP Photo/Mohammad Sajjad)

  • Pakistani men, left, check the damage caused by a car bomb explosion, while army soldiers gather at the site in the Pakistani town of Darra Adam Khel in the troubled Khyber Pakhtunkhwa province bordering Afghanistan, Saturday, Oct. 13, 2012. (AP Photo/Mohammad Sajjad)