Pompeo told a U.S. Senate committee that he had "no announcements" on waivers, particularly in an unclassified setting.
U.S. Secretary of State Mike Pompeo said on Wednesday that President Donald Trump will continue to increase pressure on Iran, but declined further comment on the possibility of waivers for countries that import Iranian oil.
Tehran has also threatened to disrupt oil shipments through the Strait of Hormuz in the Gulf if the United States tries to strangle Iran's economy by halting its oil exports.
"I can assure the rest of the world that President Trump will continue to ratchet up the pressure on the Islamic Republic of Iran so that their behaviour will change".
The US reimposed sanctions on Iran a year ago after pulling out of the Iran nuclear deal.
Iranians rallied on Friday against the US's decision to designate the country's powerful Revolutionary Guards as a foreign terrorist organization.
In an interview with CNN's Christian Amanpour on Thursday, Iran's UK Ambassador Hamid Baeidinejad said the American military forces in the Persian Gulf region were in a volatile situation and it wouldn't be wise if they chose to take action against the IRGC. Washington had previously sanctioned many entities and individuals linked with IRGC but had not formally designated it as a terror group.
Leader Sayyed Hassan Nasrallah said that all options were on the table if the U.S. "threatened" the Iranian Regime as Iran and its allies hold "many strong cards".
"There are measures which, if taken by the Americans.who said they will remain without response?"
The members of Iranian parliament at Tuesday's session showed up in official uniforms of IRGC to announce their support and solidarity with the forces. Iranian Supreme National Security Council, in retaliation, has recognized the US Central Command (CENCTOM) as a terrorist organization.