Pakistani national elections will take place before February 15, President Pervez Musharraf said on Thursday, after Western allies and opponents had demanded polls be held on time and emergency rule scrapped.

Pakistan had been scheduled to hold elections by mid-January until the general imposed emergency powers on Saturday and suspended the constitution.

We are looking at a date where we can dissolve all the assemblies simultaneously and hold the election simultaneously for the national assembly and four provincial assemblies, Musharraf told official media after chairing a meeting of the National Security Council.

Having calculated all this, we must hold elections before the 15th of February, 2008, he added.

I have been saying for the last few months that elections will be held on schedule ... It was my commitment and I am fulfilling it.

He said that stepping down as army chief, which he has vowed to do, depended on a Supreme Court ruling on whether he had been eligible to stand for re-election last month while still in uniform.

When they allow this notification, that is the time when I can take oath as president and remove the uniform, said Musharraf, who has purged the Supreme Court bench and filled it with more amenable judges.

PUSH FROM BUSH

Musharraf's announcement came just hours after U.S. President George W. Bush called him for the first time since Saturday's announcement, urging him to hold elections and quit as army chief.

The United States had hoped former prime minister Benazir Bhutto would end up sharing power with Musharraf after the elections, but the imposition of the emergency left U.S. policy toward Pakistan in disarray.

Washington regards Musharraf as a valued asset in the fight against al Qaeda and the Taliban.

I had a very frank discussion with him, Bush said of Musharraf.

My message was that we believe strongly in elections and that you ought to have elections soon and you need to take off your uniform. You can't be the president and the head of the military at the same time, Bush told a news conference.

Bhutto's party said on Thursday that police had arrested thousands of its activists overnight as a crackdown on Musharraf's opponents deepened.

Police had already detained hundreds of lawyers and other opposition figures and supporters since Saturday.

(Reporting by Kamran Haider, Simon Gardner in ISLAMABAD, Ovais Subhani in KARACHI, and Kristin Roberts in WASHINGTON; editing by Roger Crabb)