A telecommunications official confirmed the government had shut down mobile services but said the move was temporary.
Nadim Baba, reporting for Al Jazeera from Islamabad, said:" [Chaudhry] was making an appeal using his mobile telephone, appealing to the lawyers to carry on their campaign of street protests demanding the restoration of the constitution and the lifting of the emergency measures.
"The remarks were being carried live on state television when suddenly the mobile phone line went dead."
Police arrested more than 100 people on Tuesday as they demonstrated against the emergency rule declared by Pervez Musharraf, the Pakistani president.
Bhutto in Islamabad
Later in the day, Benazir Bhutto, Pakistan's former prime minister, arrived in the capital from Karachi and immediately proceeded to talks with political leaders on the state of emergency, Nadim Baba said.
Despite a huge police deployment, hundreds of supporters were there to catch a glimpse as she headed to her Islamabad residence.
|After emergency was imposed, Bhutto said|
she had no plans to meet Musharraf [AFP]
Video footage showed Bhutto outside the airport in an open-topped vehicle, waving at the assembled crowd of flag-waving supporters.
She has said she has no plans to meet Musharraf.
"I am going to hold discussions with the leadership of other parties on the current situation and chalk out a joint strategy with them," Bhutto said as she left Karachi airport.
She said that a meeting with Musharraf was "not in her schedule during her stay in Islamabad".
Bhutto may hold a public rally in Rawalpindi this week, which would present a huge challenge for the security forces.
Earlier on Tuesday, around 50 lawyers were arrested in the eastern city of Lahore as they tried to assemble on the premises of the provincial high court, a senior officer said.
"Musharraf has many enemies in his country and I believe with Bhutto as PM there would be more people supporting the government"
Howahr, Doha, Qatar
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Akram Beg, a Lahore police official, said the administration had imposed a ban on gatherings of more than five people, and police had picked up those who were defying the restriction.
About 50 others were arrested in various cities across Pakistan, including in the central city of Multan when hundreds of police blocked about 1,000 lawyers from leaving a district court complex to stage a street rally.
Musharraf has detained hundreds of lawyers and opposition politicians since declaring the emergency on Saturday.
The move was seen an attempt to pre-empt the possibility of the supreme court invalidating his re-election to the presidency last month as he still retains his post as head of the army.
Musharraf has already replaced a number of judges from the supreme court benches.
Four more were sworn in on Tuesday, taking the total to nine, still far short of the total of 17.
The arrests came a day after officials said that an election would be held in early 2008.
George Bush, the US president, has urged Musharraf to lift the emergency the general imposed over the weekend, quit the military and hold elections.
The US has put future aid to Pakistan under review, having provided $10bn in the past five years, and postponed defence co-operation talks with Pakistan due this week.
The imposition of emergency rule had raised considerable doubts whether parliamentary elections, expected in January, would go ahead as scheduled.
Pakistan's cabinet discussed possibly delaying by up to three months crucial parliamentary elections, a minister said on Tuesday.
"The issue of holding elections was discussed at length, and after attending the cabinet meeting I feel that the elections may be delayed by two months," he told the Associated Press news agency on condition of anonymity.
"There will not be a delay of elections for longer than three months.
"There is no final decision."