ISLAMABAD (AP) -- Ahead of planned massive anti-government protests, Pakistan's capital feels like a city preparing for a siege.
Shipping containers block roads leading into central Islamabad, placed by security forces hoping to halt protesters supporting either a fiery anti-government cleric or a cricket star-turned-politician. Police in riot gear can be seen taking up positions across the city as authorities suspended mobile phone service in some areas. Meanwhile, those worried the government may cut off fuel shipments to slow demonstrators have lined up at gas stations.
The protests Thursday represent the strongest challenge yet to the government of Prime Minister Nawaz Sharif, just a year after he took office in the first democratic transfer of power in a country long plagued by military coups. And how the country reacts to calls for Sharif's ouster will show how far its nascent democracy has come.
"I think there is going to be a test of wills in Islamabad," said Rasul Bakhsh Rais, who heads the Institute for Strategic Studies.
Two men are at the forefront of challenges to Sharif.
The first is Tahir-ul-Qadri, a Pakistani cleric who's also a Canadian national. He commands a loyal following of thousands through his network of mosques and religious schools in Pakistan. Last year, Qadri held a protest in the capital calling for vaguely worded election reforms ahead of the country's May poll, grinding life in Islamabad to a halt. His followers already clashed with police this weekend.
The other is Pakistan's former cricket legend Imran Khan. His Pakistan Tehreek-e-Insaf party is the third-largest political bloc in parliament. Khan's attempts to win followers in Punjab province, the power base for Sharif and his Pakistan Muslim League-N, have rattled the ruling party.
Both men want the government to step down and new elections be held. Khan alleges last year's vote is invalid due to widespread rigging by government supporters.
"A sea of people is coming to Islamabad and they are peaceful and you cannot stop them," Khan said Tuesday.
Both men picked Pakistan's Independence Day for their rallies, the day marking when the country became its own nation carved out of India in 1947. In the opaque world of Pakistani politics, where security services remain powerful, there has been wide speculation that the two men have other internal support, something they've denied.
Their representatives met Tuesday to discuss their strategy. Shah Mahmood Qureshi, a former foreign minister backing Khan, said after the meeting that protesters would not resort to violence, but would resist any effort to impose martial law.
"We are working on a national agenda to bring real democracy in the country," Qureshi said.
Sharif, himself overthrown in the 1999 coup that brought former army chief Pervez Musharraf to power, is taking no chances. He has met regularly with top advisers, and the government has invoked a rarely-used article in the constitution allowing the military to step in to maintain law and order if needed.
In a televised address Tuesday, Sharif said a Supreme Court committee would look into claims of fraud in last year's election. He also warned that "no one will be allowed to create anarchy and play with the constitution."
"It is not possible that in presence of parliament, decision should be taken on streets," he said. "Here is nobody's monarchy nor here is there any dictatorship."
After Sharif's address, Khan said the prime minister would have to resign before any probe.
Hanging over the planned rallies has been the question of whether the Pakistani military has had any role in fomenting opposition to a government with which they have increasingly been at odds.
This nuclear-armed country of 180 million people has had three military coups since independence. The military hasn't commented on Khan or Qadri but generally says it does not meddle in politics.
Relations between Sharif and the military frayed when the government decided late last year to prosecute Musharraf for high treason. The military also has bristled at accusations that its powerful spy chief was behind the assassination attempt of a powerful television anchor.
Sharif and the military also are believed to be at odds with opening up trade with India, which it has fought in three wars, as well as whether to negotiate with Taliban militants.
But regardless of who is behind the protests, many believe Sharif won't back down from the challenge.
"This time around he is going to stand his ground, firm and polite, no matter what the consequences," said Rais, the analyst.
Associated Press writer Zarar Khan contributed to this report.
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