It was Bush's first direct contact with Musharraf since the Pakistan president imposed emergency law.
Bush has been questioned on the soft stance taken on the military crackdown in Pakistan compared to the hard line when Myanmar's ruling generals crushed peaceful demonstrations.
In defending his response to both situations, Bush said different tactics were required "to achieve the common objective" because Pakistan, unlike Myanmar, was already on the path to democracy.
Outside parliament, police pushed back hundreds of PPP supporters who tried to overrun a security zone.
Pakistani police also vowed to stop a rally by Bhutto planned for Friday in the garrison town of Rawalpindi, which lies south of Islamabad.
"Despite the protests being limited in scale and quite minor, the police fired tear gas [at Bhutto’s supporters]," Al Jazeera's Nadim Baba reported from Islamabad.
|Bhutto has stepped up her rhetoric, calling |
on supporters to confront Musharraf [AFP]
"They had gathered at the beginning of the parliament session which the PPP had decided to boycott, along with all the other members of the opposition."
Hundreds of people, mostly lawyers and opposition politicians, have been detained in Pakistan since Musharraf imposed emergency rule on Saturday.
"This was day one of our protest," Qamar Zaman Kaira, a PPP member within Pakistan's national assembly, told Al Jazeera.
"We will offer the other parties ... who are serious in restoring democracy and civil rule to Pakistan [our support]," he said.
Supporters of the Pakistan Muslim League Nawaz group, which is headed by Nawaz Sharif, a former prime minister, also protested against Musharraf in the city of Lahore on Wednesday.
Meanwhile, Kamal Hyder, Al Jazeera's correspondent in Pakistan, reported that members of the legal fraternity had also protested in Peshawar against Musharraf's imposition of emergency rule.
Plan for rally
Babar Awan, a senior member of the PPP, said that the party would not observe constraints under emergency law.
"We denounce the government ban, and want to make it clear that our supporters and leaders will reach Rawalpindi for the rally," he said.
However, police said they would use current emergency powers to force an end to any protests.
Saud Aziz, Rawalpindi's police chief, said: "If they try to flout the ban, the law would take its course."
Javed Akhlas, the mayor of Rawalpindi, said police would be out in force to prevent anyone reaching the park where Bhutto hoped to address supporters.
"We will ensure that they don't violate the ban on rallies, and if they do it, the government will take action according to the law," he said.
Bhutto, a Pakistani prime minister on two former occasions, also called on Wednesday for supporters to march from Lahore to the capital on November 13 if Musharraf does not rescind the emergency order.
"It does seem to be another level that Bhutto has stepped up her rhetoric," Baba reported.
"Significantly, for the first time this week she has called her protesters on to the streets. She knows she commands some sort of support among the grass-roots, not just in her stronghold of Karachi but here in Punjab," Baba said.
Bhutto wants Musharraf to announce the date of presidential elections mooted for January, restore constitutional rule and quit as head of the army.
Bhutto, in her strongest comments since Musharraf imposed emergency rule, said the world must make Pakistan's military leader revoke his measures or tell him to quit.
"If he doesn't, then I believe that the international community must choose between the people of Pakistan and him," Bhutto said in an interview with British TV broadcaster Channel 4.
"I am very worried and angry - Musharraf should realise that we don't need him"
Avas, Islamabad, Pakistan
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She returned to Pakistan on Tuesday, but said that a meeting with Musharraf was "not in her schedule during her stay in Islamabad".
Musharraf and Bhutto had been in contact for several months prior to her return, discussing a possible power-sharing deal.
He granted her an amnesty on corruption charges in October to allow her to return home.
Also on Wednesday, Imran Khan, the Pakistani cricketer turned politician, also called for protests against Musharraf in a video broadcast on the private Geo TV.
"If we don't resist, it will take Pakistan on the path of destruction," Khan said in the short video message.
In Washington, John Negroponte, the deputy US secretary of state, said on Wednesday that continued engagement with Pakistan was the "only option" despite Musharraf's declaration of emergency rule.
"We cannot afford to return to our past estrangement," he said in prepared testimony to the Foreign Affairs Committee of the House of Representatives.
"Partnership with Pakistan and its people is the only option."
Source: Al Jazeera and agencies