Zardari will attend the memorial of Richard Holbrooke, who was the US special representative to Afghanistan and Pakistan until his sudden death last month, and meet US Secretary of State Hillary Clinton, the ministry said.

"The president left for the United States on Wednesday evening. He will attend the memorial of Richard Holbrooke on Friday and he has several meetings arranged in the United States," Basit said.

"He will meet with Secretary of State Hillary Clinton, (but) no meeting is scheduled," with President Barack Obama, Basit added.

In a further gesture of conciliation, Zardari's office said the president spoke to all opposition party leaders on Wednesday to inform them of his plans before departing for the United States.