BRUSSELS, Belgium (AP) _ NATO officials say the cost of bringing three former Warsaw Pact members into the alliance is ``manageable'' _ and far below estimates by the Clinton administration.

The North Atlantic Treaty Organization estimates it will cost $1.5 billion over 10 years to allow Poland, Hungary and the Czech Republic to join. The three nations were invited to participate after a summit in July.

``It is a manageable cost,'' NATO Secretary-General Javier Solana said, adding there was broad agreement among member nations.

U.S. officials have estimated the cost of incorporating the three countries at between $27 billion and $42 billion, but NATO officials say the alliance's cost study is more reliable.

The study was based on a sophisticated military analysis carried out by the supreme allied commander in Europe, Gen. Wesley Clark, his staff and by the NATO Military Committee, the alliance's military think tank.

``The conclusions started from a military assessment ... a solid basis to have a final decision,'' Solana said.

NATO's permanent representatives in Brussels approved an internal report estimating the cost of the first phase of expansion at between $1.3 billion and $1.5 billion. The report will be presented to NATO's 16 defense ministers at their meeting here next week.

NATO's figures represent the total ``common costs'' to NATO members _ such as hooking new members up to the communications and air defense systems.

Other studies have included costs of modernizing new members' military forces, something the new members must pay themselves, or have considered expansion by four or five countries rather than three.

All preparatory work has been completed for the accession of Poland, Hungary and the Czech Republic, and their foreign ministers have been invited to Brussels next week to sign the official protocols.

The enlargement still requires ratification by legislatures of the 16 current NATO members, including a two-thirds vote in the U.S. Senate.