The Helms-Burton Act and the Iran-Libya Sanctions Act aim to stop foreign companies from investing in Cuba, Iran and Libya.

Following are each law's main provisions and Monday's changes:

HELMS-BURTON

Formally known as the Cuban Liberty and Democratic Solidarity Act, the law was enacted in March 1996 in an attempt to squeeze off foreign investment in Cuba and try to expand the U.S. embargo against the communist-ruled nation.

One provision of the law requires the administration to bar from entry into the United States executives and their families from companies that do business with expropriated property in Cuba.

President Clinton agreed Monday to ask Congress for the ability to waive that sanction as it relates to Europeans. Clinton has repeatedly frozen another provision that would allow Americans whose properties worth more than $50,000 were confiscated after the 1959 revolution to sue in U.S. courts the foreign companies that benefit from use of those properties.

IRAN-LIBYA SANCTIONS ACT

Introduced by New York Sen. Alfonse D'Amato, the 1996 law stipulates automatic sanctions against any company that invests more than $40 million per year in the hydrocarbon sector in Iran and Libya.

The law gives the president a list of seven sanctions to chose from and in most cases it requires the application of at least two of the measures.

The penalties include barring U.S. banks from making loans of more than $10 million to targeted companies, banning the companies from selling goods to the U.S. government, and barring all U.S. imports from the companies.

The law allows the president to waive sanctions against a company if is it deemed to be in the U.S. national interest.

Clinton invoked that provision Monday to exempt a consortium led by France's Total from the sanctions.