Many children face struggle to survive; see A5.UNITED NATIONS (AP) - President Bush will join more than 70 other world leaders at the Children's Summit but is not prepared to sign a treaty calling for basic rights for children, a senior U.S. official said Friday.

Conservatives in Congress have criticized the document because it forbids the death penalty for people under the age of 18 and because it does not define a fetus as a child and thus protected by the convention.At the gathering, Bush will announce a U.S. program to wipe out measles, polio and other childhood diseases in America and will pledge more funds for children suffering from AIDS, said the U.S. official, speaking on condition of anonymity.

The United States, along with the rest of the nations represented at the meetings today and Sunday, also will announce new strategies to reduce infant mortality, illiteracy and to make health care more available to mothers and children, among other goals.

The U.S. delegation will include Bush, Secretary of State James A. Baker III, Mother Hale, a Harlem grandmother who cares for AIDS-infected babies, and Health and Human Services Secretary Louis Sullivan.

One of the major purposes of the Children's Summit is to seek more signatures and ratifications of the Convention on the Rights of the Child. The treaty, adopted last November by the General Assembly, went into effect this month after at least 20 nations had ratified it.

At least 43 nations have ratified the convention, which requires nations to guarantee the survival of children, their protection, development and the right to participate in planning their upbringing, as well as freedom of thought and conscience.

More than 100 other countries have signed the convention, indicating their intention to ratify it. Ratification is complete when a nation has brought its laws into conformity with the convention and its legislature has adopted the document.

The official said the White House, State Department, Justice Department and other agencies are still studying the ramifications of the convention, and an eventual U.S. signature is possible.

The United States has signed some past U.N. conventions on the assumption that any discrepancies with U.S. law could be resolved later. One example was a measure that promotes international cooperation to apprehend drug traffickers and seize their assets.

James Grant, the director of the U.N. Children's Fund, said he believed the United States would sign the convention next year. The world leaders will arrive today for an informal luncheon and a formal evening banquet.

Among the leaders expected to attend the summit are Britain's Prime Minister Margaret Thatcher, Argentine President Carlos Saul Menem, Canadian Prime Minister Brian Mulroney, Czechoslovak President Vaclav Havel, West German President Richard von Weizsacker, Japanese Prime Minister Toshiki Kaifu, Mexican President Carlos Salinas de Gortari and many others.

The summit will cost up to $5 million, the U.S. official said.

Grant said all or most of that is being paid by donations from governments, private organizations and individuals.

The United States has contributed $150,000 through the Agency for International Development, and the U.S. committee of UNICEF gave $300,000, the U.S. official said.

Hundreds of journalists have received special accreditation to cover the event, including about 40 children from the newspaper Children's Express, and other papers, UNICEF officials said.