West German authorities said Saturday that initial results of the international investigation into the Lockerbie Pan Am jet bombing indicate that the explosive was smuggled aboard Flight 103 in London rather than Frankfurt.

The Interior Ministry and the Federal Prosecutor's Office issued huffy denials of Saturday's front-page Times of London report that investigators had concluded that the bomb was placed on the flight in Frankfurt."The evidence we have so far is contradictory" to the newspaper's assertions, Interior Ministry spokesman Michael-Andreas Butz said. Neither he nor the prosecutor's office provided details.

British and U.S. officials also denied the London report. A senior U.S. law enforcement official in Washington termed it "just not accurate." But the British and U.S. officials did not join the West German spokesmen in suggesting that indications so far point to London as the site where the explosive was planted.

"It wouldn't be true to say that we have established one way or the other whether the bomb was planted here or there. It is speculation," a spokesman for the Scottish police investigation team said in a telephone interview from Lockerbie.

"We don't know where it was put aboard," the U.S. official said, adding that investigators also are looking at the plane's previous stops.

Flight 103 originated in Frankfurt on a Boeing 727 bound for London. Forty-nine passengers from Frankfurt and their luggage changed planes in London and got aboard the flight's continuation on the 747 bound for New York.

West German officials clearly were irritated by Saturday's London report, which apparently was based on information provided by British officials. Britain "apparently is all too ready to shift this thing from London to Frankfurt," a high-ranking Bonn government source said. West German authorities have said that security precautions at the Frankfut airport were better than those at London's Heathrow Airport.

Despite their insistence that Frankfurt probably was not the site where the bomb was planted, West German authorities are actively studying the possibility of a link between the bombing and the discovery in October in West Germany of what prosecutors have called a terrorist cell of a Syrian-based, hard-line group of the Palestine Liberation Organization.

"We pursue that (possibility) with great attention," Federal Prosecutor's Office spokesman Alexander Prechtel said Friday.

The investigation of the alleged members of the Popular Front for the Liberation of Palestine-General Command, or PFLP-GC, yielded the biggest haul ever in West Germany of terrorist weapons when police raided hideouts two months ago, Prechtel said.

One cache included a double-trigger detonator apparently designed to be used on a bomb to be smuggled past luggage screening devices employed at the Frankfurt airport.