Pakistan shut down mobile phone networks overnight in major cities to prevent Taliban and Al-Qaeda attacks as celebrations began for the biggest Muslim festival of the year.
The draconian security measure kicked in on Sunday at 8:00 pm (1500 GMT), at a time when millions ordinarily telephone friends and relatives with greetings for Eid al-Fitr. Networks were working again on Monday mid-morning.
Karachi and Lahore, Pakistan's two largest cities, and the troubled city of Quetta, in the insurgency-torn province of Baluchistan, were among the places where networks were suspended.
"We regret that it had to be suspended in some cities due to the risk of terrorist attacks," Interior Minister Rehman Malik was quoted as saying by state TV.
"We regret inconvenience caused to youths and children."
Terrorists were plotting to target "a few areas of Punjab province", of which Lahore is the capital, the minister said. Sindh province, where Karachi is the capital, and Baluchistan were also targets, he added.
Authorities feared that mobile telephones could be used to coordinate attacks or trigger a remote-controlled bomb.
The Eid festival marks the end of the holy fasting month of Ramadan and, in Pakistan, is accompanied by a three-day public holiday, until Thursday.
The country has been on alert for Eid and security forces stepped up their presence in major cities as celebrations got under way.
On Thursday, heavily armed militants stormed an air force base, the worst attack on a military facility for more than a year, sparking clashes that left 10 people dead.
On the same day, gunmen in military uniforms pulled 20 Shiite Muslim travellers from vehicles and shot them dead in the northwestern district of Mansehra.
Pakistan says 35,000 people, including more than 3,000 soldiers, have been killed as a result of terrorism since the 9/11 attacks and the 2001 US-led invasion of neighbouring Afghanistan.