WASHINGTON - U.S. President Donald Trump will increase pressure on Iran, U.S. Secretary of State Mike Pompeo said on Wednesday, but he declined specific comment on whether the administration would continue sanctions waivers for countries that import Iranian oil.Pompeo told a U.S. Senate committee he had "no announcements" on whether Washington would continue waivers to some countries that import Iranian crude, or for Iran's civilian nuclear program, now that Trump has withdrawn the United States from the 2015 international nuclear agreement with Iran and reimposed sweeping sanctions."I can assure the rest of the world that President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 behavior will change," Pompeo said.Senator Ted Cruz and some other Republican members of the Foreign Relations Committee urged Pompeo not to continue the oil waivers when a deadline comes up next month, saying Iran's exports are generating billions of dollars in revenues for its government.In response, Pompeo said, "We've been clear about our objective in getting Iran to zero (imports) just as quickly as we possibly can, and will continue to do that."When Trump withdrew from the nuclear pact in November, he gave a six-month waiver to eight nations, allowing them to import some Iranian oil until early May. India, Iran’s top oil client after China, was allowed to buy about 9 million barrels a month.Reuters reported on Tuesday that Indian refiners are holding back from ordering Iranian oil for loading in May while they wait for word on the sanctions waiver.Separately, Trump said on Monday he would name Iran's elite Islamic Revolutionary Guard Corps a terrorist organization, an unprecedented step that drew Iranian condemnation and raised concerns about retaliatory attacks on U.S. forces.Pompeo said he foresaw a significant impact from that decision. "If you're the general counsel of an Asian bank or a European bank, your world changed when that designation came out yesterday," he said.