A Senate Democrat threatened Wednesday to block the president's Treasury Department appointments as the Bush administration reconsiders a rule for companies that sell food and agricultural products to Cuba.

Sen. Max Baucus (search) of Montana, the top Democrat on the Senate Finance Committee, said a potential revision threatens to obstruct trade and "takes this administration's dangerous obsession with Cuba to a whole new level."

"I will not sit idly by if the Treasury Department (search) attempts to rewrite legislation Congress intended to facilitate trade with Cuba," he said.

Treasury Department spokeswoman Molly Millerwise said, "We're anxious to get our nominees confirmed, and we will work collaboratively with Congress to achieve that goal."

Beginning a few weeks ago, companies that sell food and agricultural products to Cuba found that payments were not being credited to bank accounts in the United States, said John Kavulich, president of the U.S.-Cuba Trade and Economic Council Inc. (search) Banks confirmed receipt of payments from Cuba but did not credit the accounts of exporters on instructions from the U.S. government.

The Treasury Department's Office of Foreign Assets Control (search), which administers sanctions policy, has since let transactions proceed on a case-by-case basis.

Banks and OFAC have questions about whether a 2000 law permitting agricultural trade with Cuba requires that U.S. exporters be paid before shipping their products to Cuba.

An embargo against Cuba bans most U.S. exports to the country with a few exceptions, including certain food and agriculture products.

Some exporters currently ship products to Cuba before getting paid, but Cuban importers do not get the goods until they pay the U.S. exporter. Baucus wants OFAC to let exporters stick with their current shipping and payment practices.

Josh Markus, a Florida attorney and former American Bar Association (search) international law officer, said the government might look askance at the delayed payments because U.S. laws prohibit companies from extending credit to the Cuban government.

"The U.S. government has taken a much harder line on many things for Cuba," he said.

A government official, speaking on condition of anonymity, said guidance will be issued soon.

Kavulich said switching the policy to require payment in advance "will not result in an insurmountable commercial environment" but will make transactions more complicated.

President Bush has called for more stringent enforcement of provisions that forbid most economic activity and travel with Cuba.

President Kennedy imposed economic sanctions against Cuba in 1963 during the Cold War. The policy aims to isolate the Cuban government economically and deprive it of U.S. dollars, the government says.