Michael Bowman of Capitol Hill contributed to this report.
WASHINGTON - Iran said Monday it has quadrupled its uranium enrichment capacity as the war of words between Tehran and Washington shows little sign of cooling off.
Iranian officials say the uranium will be enriched for civilian energy uses, far below weapons grade as spelled out in the 2015 nuclear agreement.
Enriching uranium means concentrating the element's radioactive component. Natural uranium has less than one percent U-235, while uranium for electric power production is around four percent pure and weapons-grade material is refined to contain about 90% of this active ingredient.
Iran could soon exceed the amount of material it is allowed to stockpile under the deal.
Iranian President Hassan Rouhani announced two weeks ago he is pulling out of some parts of the six-nation nuclear deal, including the condition that Iran sell excess amounts of uranium to other nations.
Rouhani has threatened to move Iran closer to weapons-grade enrichment unless it sees promised economic relief from the deal by early July.
President Donald Trump pulled out of the nuclear agreement deal one year ago. He re-imposed sanctions on Tehran and has threatened other sanctions on countries that still do business with Iran. Trump's decision has made the Iranian economy, already in tatters, even weaker.
Trump's moves have helped set the stage for the current increased tensions between the United States and Iran.
Trump tweeted Sunday, 'If Iran wants to fight, that will be the official end of Iran. Never threaten the United States again!'
Foreign Minister Mohammad Javad Zarif responded to what he called 'genocidal taunts' by reminding Trump that 'Iranians have stood tall for a millennia while aggressors all gone,' including Genghis Kahn and Alexander the Great. 'Try respect. It works,' Zarif tweeted.
Senior Trump administration officials plan to brief Congress Tuesday about the military threat it says Iran poses in the Middle East.
Republican Senator Lindsey Graham said Monday that after a briefing from national security adviser John Bolton, 'It is clear that over the last several weeks Iran has attacked pipelines and ships of other nations and created threat streams against American interests in Iraq.'
Graham tweeted, 'The fault lies with the Iranians, not the United States or any other nation. If the Iranian threats against American personnel and interests are activated, we must deliver an overwhelming military response. Stand firm Mr. President.'
Monday in the Senate chamber, Democratic Senator Tim Kaine said, 'It would be absolute lunacy for the United States to get involved in another war right now in the Middle East. I think it would be devastating to be in a war with Iran and, in my view unconstitutional to be in a war with Iran at a president's say-so. ... It's Congress that declares war, not the president. It's not for a president to say it and start it. It's not for a president to, by a series of provocations, blunder us down the path where war becomes inevitable.'
Later, Democratic Senator Chris Murphy tweeted: 'No one should defend the actions Iran has taken - they've been out of control for years - but dumb wars start when each party mistakenly believes that the other party's defensive or reactive actions are actually offensive and proactive.'
The U.S. Navy's Fifth Fleet said it has increased maritime patrols and exercises in the Arabian Sea that highlight the 'lethality and agility to respond to threat.' The Pentagon has already sent bombers to the region.
Iranian leaders say they do not want war, but have shown no interest in talks with the U.S.
Meantime, Saudi Arabia said Monday it intercepted two missiles it says were fired by Iranian-backed Houthi rebels in Yemen. One missile was stopped over the city of Taif and the other over Jiddah.
The Houthis deny involvement.
The Saudis have said they do not want war, but will fight to protect their interests.
The Saudis also blame the Houthis for a drone attack on two Saudi oil-pumping stations last week, and the U.S. says it suspects Iran was behind the sabotage that damaged four tankers off the coast of the United Arab Emirates last week. Two of the tankers were Saudi.
Saudi Arabia is leading a coalition helping the Yemeni government fight the Houthi rebels. Iran has not denied supporting the Houthi cause, but has said it does not supply weapons to them.