Karachi: Cellphone and wireless services in the federal and two provincial capitals including Karachi were switched off till midnight on Friday over security fears.
A minister said the cities could be targeted by terrorists.
The ban came as security measures for the Muharram processions reached a peak.
A complete ban on motorcycles was imposed in Hyderabad, the second-most populated city in the southern Sindh province.
Interior Minister Rahman Malek after consulting the provincial government ordered the closure of mobile phone services in Karachi and Quetta, the capital of Balochistan and one of the highly sectarian sensitive city.
The services of cell and wireless phone were suspended from 12 Friday noon till midnight.
In Islamabad, the suspension of mobile and wireless phones came into effect at 3pm.
Ban on riding on motorcycle would continue till the end of Muharram processions.
Addressing a press conference Malek said that Karachi and Quetta were put on high alert in view of intelligence reports that suggest higher chances of terrorist attacks. The minister said there were some reports that terror could also strike Islamabad.
There were reports that in Quetta the cell phone service might be banned for the 9th and 10 of Moharram, falling on Saturday and Sunday.
Besides, the government of Khyber Pakhtunkhwa was also considering suspending the cell phone services in six of its districts which were considered to be vulnerable to sectarian attacks.
Meanwhile, some four suspects were rounded up from Ancholi town, the Shiite area. The Shiite mourners nabbed two suspects and handed them over to the paramilitary rangers. Soon after the incident the Shiite scouts also rounded two other suspects.
Fearing terrorist attacks, the provincial government already announced closure of the schools and its offices on Friday.
Meanwhile, this year saw violent sectarian clashes in the country as it witnessed a new phase in the long history of sectarian feud, the Dawn said Friday.
With attacks on religious places and processions, 2012 could be a “particularly bloody one” in terms of sectarian conflict.
The rising level of sectarian tension should have prompted security agencies to pro actively crack down on violent elements in the society, the newspaper said.
“The writing was on the wall about what was to come in the first 10 days of the month. But given that these groups were not identified and targeted earlier, the only option left over the next handful of days is to focus even harder on prevention.”
Although extraordinary measures are in place, from public holidays to cellphone service bans for the next three days, the culmination of the Muharram mourning, some of which would be highly inconvenient for the citizens, daily said.