(VOVworld)- The U.S. Senate resoundingly approved on Friday expanded sanctions on global trade with Iran's energy and shipping sectors, its latest effort to ratchet up economic pressure on Tehran over its nuclear program. The new package, which keeps in place exemptions for countries that have made significant cuts to their purchases of Iranian crude oil, would be the third round of sanctions in a year if passed into law. The existing sanctions have already hurt Iran's economy, but it is uncertain whether the additional measures will stop or slow Iran's nuclear program. Washington says Tehran is enriching uranium to levels that could be used in nuclear weapons. Iran says the program is for peaceful purposes.