WASHINGTON - The US senate on Monday approved a new sanction bill against Iran's energy sector, in an effort to further pressure Tehran on its disputed nuclear program.

The move came ahead of the next round of talks on Iran's nuclear program due to start on Wednesday in Baghdad, the capital of Iraq. The talks will be attended by Iran and six world powers, including Germany, France, Russia, the United Kingdom, the United States, and China.  

In a voice vote, the US senate unanimously passed the bill that would sanction Iran's Revolutionary Guard Corps and expand penalties for energy companies that set up joint ventures with the Islamic republic.

The bill requires companies listed on the US stock market to disclose business ties with Iran to the US financial regulatory authorities.

The bill also targets individuals and entities that help Iran to crack down on its protestors. The property of the designated companies will be frozen and the targeted individuals will be denied visa access to the United States, according to the bill.

The United States has already targeted Iran's central bank and oil exports for expanded sanctions in its continued efforts to press Tehran to stop its uranium enrichment activities. The West has been accusing Iran of trying to develop nuclear weapons under a civilian disguise, while Tehran always rejects such charge.