The settlement, whose broad outlines were reported last week, came after a long-running negotiation that had strained ties between the United States and France.

Conflicts Alongside the oil issue, several border disputes with Sudan continue to strain ties.

The growing bilateral trade deficit could strain ties between the United States and China.

The BBC looks at the background to the Preah Vihear dispute, which continues to strain ties between Thailand and Cambodia.

Mr. Venezia recommends drafting a formal agreement with a repayment schedule, to avoid straining personal ties.

But Mr. Shamir, they think, is not willing to strain ties with the U.S. to the point of losing his prime ministership.

Retaliation of that kind would further strain economic ties at a time when the United States and Europe are already fighting skirmishes over genetically modified products and aircraft noise.

But some experts said it showed how even subtle changes in approach could strain ties.

Further straining American ties with the Caribbean is a 90 percent drop in United States aid for the region between 1985 and 1995.

Lord Robertson also said the initial reluctance by the United States to consult NATO about Afghanistan when Washington first intervened to topple the Taliban had strained ties within the alliance.