Berger said Clinton should only sign the bill if a provision were added to it authorizing the president to waive the retaliatory sanctions.

In the past, China suggested that if human rights discussions were not linked to threats of retaliatory sanctions, it might pay them more heed.

So the meter has been running since March as the European Union levies billions of dollars in retaliatory sanctions on a wide range of American products.

The United States can impose retaliatory sanctions or seek compensation if the foreign country refuses to eliminate the barriers.

Two years ago, India's nuclear tests provoked worldwide condemnation and retaliatory sanctions by the United States.

The retaliatory sanctions were the first to be imposed since 1952, when the Netherlands acted against the United States in a dispute over dairy products.

At the same time, Russian officials made it clear that they do not support retaliatory sanctions or other steps to isolate Iran's leadership.

But both sides must grapple with influential domestic constituencies and broad diplomatic concerns as they ponder whether and how to impose retaliatory sanctions.

It's not clear exactly what "appropriate action" they meant, but the transportation secretary possesses the power to impose retaliatory sanctions on foreign airlines.

If no compromise was reached and the American position was upheld, the process could end with the United States' imposing unspecified retaliatory sanctions in about 18 months.