"I am very worried and angry - Musharraf should realise that we don't need him"
Avas, Islamabad, Pakistan
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"As a result of what has happened, there could be some timing differences but no decision has been made."
He said the emergency announced on Saturday would be as short as possible and that 400-500 people are being held under "preventive detentions".
The president's order to suspend the country's constitution has been condemned across the world.
Condoleezza Rice, the US secretary of state, on Sunday said the US will review its multi-billion dollar aid programme to Pakistan over the move.
She said: "Obviously we are going to have to review the situation with aid, in part because we have to see what may be triggered by certain statutes."
But Musharraf has so far remained defiant, and in a taped address to the nation, he said that "not acting now would have been suicidal for Pakistan".
The imposition of emergency has been followed by large-scale arrests of those opposed to Musharraf.
Among those arrested are Imran Khan, a famous cricket player turned politician, Asma Jehagir, chairman of the independent Human Rights Commission of Pakistan, and Javed Hashmi, the acting president of the Pakistan Muslim League (PML) party of Nawaz Sharif, the former prime minister.
Lieutenant General Hamid Gul, former head of Pakistan's secret service, speaking by phone to Al Jazeera, said: "I have been arrested. And this is not an emergency, this is martial law.
Let's be very clear, there is no constitution today in Pakistan and I think we have created a lot of problem for Pakistan."
Iftikhar Chaudhry, the supreme court chief justice fired by Musharraf on Saturday, has also been placed under house arrest.
Private Geo TV reported the arrest of Aitzaz Ahsan, the president of the supreme court bar association.
Benazir Bhutto, a former prime minister, who raced back to Pakistan from Dubai as soon as news of the crackdown was announced, has denounced the emergency rule.
She said: "We had apprehensions that a state of emergency would be imposed but this is a situation worse than emergency because this is martial law. This is no emergency."
However, the government denies martial law has been imposed in Pakistan.
Tariq Azim, deputy information minister, said: "It's certainly not martial law. You don't see tanks and soldiers running around on the streets. We don't have any martial accords. So it is not martial law.
Sharif, who is currently in exile in Saudi Arabia, said Pakistan was heading towards anarchy and described Musharraf's decision to invoke emergency as worse than martial law.
Speaking to Al Jazeera from Jeddah, he said the imposition of emergency was unprecedented and that it was done by Musharraf to pre-empt a possible adverse supreme court ruling on his eligibility to be re-elected as president.
The ruling was expected in a matter of days.
Sharif said: "The country is in the hands now of one single man who has no respect for its fate.
"He has no respect for the constitution, he has no respect for the judiciary, he has no repsect for the law of the land.
"He is doing this to perpetuate his rule - I would say mis-rule."
In the city of Peshawar, the provincial capital of the North West Frontier Province, security was beefed up on Sunday.
In Quetta, the capital of the troubled Baluchistan province, police were put on high alert.
|Soldiers had the supreme court in Islamabad|
surrounded on Sunday morning [AFP]
Roads leading to the residences of senior government officials were also blocked.
And in Karachi, troops were out in the streets on Sunday morning to maintain a relative calm.
Paramilitary forces manned barricades in the capital Islamabad, blocking off all roads leading to the parliament and supreme court.
Witnesses said paramilitary troops had also been deployed at state-run television and radio stations.
Transmissions by TV networks, other than state-controlled Pakistan TV, remained off the air in major cities on Sunday morning.
Under emergency rule, Musharraf has banned the media from publishing anything that defamed, ridiculed or brought him, the armed forces or government, into disrepute.
Source: Al Jazeera and agencies