TEHRAN The Senate of the United States of America is to examine a bill related to extending the period of the Iran-Libyan sanctions act (ILSA) which prevent U.S. companies from investing in the two countries' oil and gas sectors.

ILSA, enacted for the first time in 1996 by the U.S. Congress, will come to an end in August and, in case approved, would be extended for five more years.

the Bush administration hopes to persuade the Congress to shorten the renewal period for the two countries' sanctions from five years to one year or two years.

U.S. President George W. Bush and some of his top aides came to office displaying keen interest in modifying the growing number of legally mandated U.S. sanctions that hamper a president's flexibility in making foreign policy and, some argue, hurt U.S. interests.

However, as in the case of Iran and Libya, domestic U.S. support for continued penalties against some countries makes it hard to alter the system.

Some of the senators maintain that the sanctions have adversely affected the process of investment in the two countries' oil and gas sectors. U.S. oil companies reject such an opinion.