A top US diplomat and British Foreign Secretary David Miliband telephoned Pakistani leaders on Thursday, amid growing political agitation in the volatile nuclear-armed country.
"US special envoy to Pakistan and Afghanistan, Richard Holbrooke, called Prime Minister Yousuf Raza Gilani today and discussed with him matters of mutual interest," the government said in a brief statement.
Miliband also called embattled President Asif Ali Zardari and discussed "matters of mutual interests," presidency spokesman Farhatullah Babar said.
Pakistan police on Thursday stopped activists from leaving the country's biggest city of Karachi, heightening tensions at the start of a mass anti-government march which has seen hundreds of demonstrators rounded up.
With nuclear-armed Pakistan in fresh crisis, lawyers, opposition supporters and civil activists planned to drive 1,500 kilometres (940 miles) from Karachi to Islamabad to demand that Zardari reinstate sacked judges.
Main opposition leader Nawaz Sharif, locked in a showdown with Zardari, has urged the masses to rise up against the civilian government, which has failed to stem a political crisis, the economic meltdown and Islamist violence.
US ambassador to Pakistan, Anne Patterson, met Sharif in the eastern city of Lahore, officials told AFP.
"The meeting continued for about one hour. Nawaz Sharif told Patterson that he and his party were struggling for the independence of judiciary, rule of law and supremacy of the constitution," the spokesman said.
US consulate spokesman Haider Hasan confirmed that the meeting took place but gave no details.
US President Barack Obama has pledged a new focus in bringing stability to Pakistan, a key ally in the "war on terror" but beset by crisis, propped up by international loans and weakened by conflict with Taliban and Al-Qaeda linked extremists.