President Clinton began a week-long European tour today by calling for an international crackdown on severe abuses of child labor, which he said includes child prostitution, pornography and even slavery.

Expanding on comments he made last week in Chicago, the president urged the International Labor Organization to approve a compact that instructs its 174 member states to "take immediate action" to eliminate such abusive conditions. The organization, holding its annual convention in Geneva's sprawling United Nations Building where Clinton spoke, will adopt the compact Thursday, its leaders said.

The child-labor speech allowed Clinton to ease into a five-nation visit that will be dominated by discussions on dealing with the war over Kosovo and the political aftermath of NATO's 78-day air campaign against forces loyal to Yugoslav President Slobodan Milosevic. His trip comes as European nations grapple with several pressing issues, including whether to continue pushing NATO-led military forces into civil wars such as the Kosovo conflict, and how and to what degree they might become militarily independent of the United States.

The trip's most dramatic moment may come on Sunday, when Russian President Boris Yeltsin joins leaders of the Group of Seven industrialized nations meeting in Cologne, Germany, where he will seek new debt relief. As Clinton landed in Geneva this morning and moved on to Paris tonight, there still was no agreement on what to do about 200 Russian soldiers at the airport in Pristina, Kosovo's provincial capital, who arrived there four days ago to the dismay of U.S. officials and those of other NATO countries.

In Geneva, Clinton was warmly received by the several hundred delegates to the labor convention. He noted that the United States already contributes heavily to the group's international program for the elimination of child labor.

"But we must go further. . .," Clinton said. "We must wipe from the earth the most vicious forms of abusive child labor. Every single day, tens of millions of children work in conditions that shock the conscience."

Such abuses, he said, include "children chained to often risky machines."

Once the organization approves the compact, he said, "I will send it to the U.S. Senate for ratification, and I will ask all other countries to ratify it as well."

Gene Sperling, a top domestic policy adviser to Clinton, said the compact should face minimal opposition in the Senate and even in developing countries that rely substantially on child labor, because it targets only "the most abusive forms of child labor."

During his motorcade to the Geneva airport after his speech, Clinton telephoned Vice President Gore to wish him luck in the formal kickoff of his presidential campaign in Tennessee.

On Thursday, Clinton will meet in Paris with French President Jacques Chirac and then Prime Minister Lionel Jospin. Friday through Sunday he will attend the G-7 summit. On Monday, Clinton is to travel to Slovenia, which broke away from Yugoslavia in 1991.

Administration sources said privately that Clinton may end this week's trip on Tuesday by visiting an ethnic Albanian refugee camp in Macedonia.