A senior State Department official reassured concerned lawmakers on Tuesday that the Obama administration is not planning to allow Iran access to the U.S. financial system or use of the U.S. dollar for transactions.

“The rumors and news that have appeared in the press ... are not true,” Undersecretary of State for Political Affairs Thomas Shannon told the Senate Foreign Relations Committee.

When Republican Sen. Bob Corker, the committee’s chairman, asked if such reports were “bogus,” Shannon answered, “As of this moment, as far as I know, yes.”

U.S. lawmakers, mostly Republicans but also some of President Barack Obama’s fellow Democrats, have expressed deep concern about recent reports that the administration might let Iran use the dollar in some business transactions.

During the hearing, some lawmakers said they remained concerned, despite Shannon’s strong denial of such reports, because of comments they see as ambiguous, such as his saying the administration was open to discussing renewal of the Iran Sanctions Act if it does not conflict with the international nuclear agreement announced in July.

“You’re like Exhibit A about why there is so much concern about this agreement,” said Corker.

Secretary of State John Kerry said on MSNBC on Tuesday that Iran deserved to see the benefits of its agreement to curtail its nuclear program in exchange for sanctions relief. Corker said Kerry seemed to contradict his conversation last night with Adam Szubin, who heads Treasury’s sanctions office, who denied the media reports.

The Iran Sanctions Act expires at the end of 2016. Some lawmakers, particularly Republicans opposing the nuclear deal, are working on renewing it months before it expires.

They say it would send a strong message to Tehran that Washington condemns its ballistic missile tests, support for Syrian President Bashar Assad and other actions contrary to U.S. interests. Nuclear deal supporters say quick action, without seeing whether Iran violates the pact, would undermine an agreement signed by Washington and its allies.

Iran test-fired ballistic missiles this month, drawing international condemnation and prompting calls for more sanctions. The Obama administration imposed new sanctions in January over an October missile test.

Shannon said the tests “violated the intent” of a U.N. resolution, but did not say they violated the resolution itself.

Shannon also told lawmakers the administration would use its veto power in the Security Council to block any sale of Russian Su-30 fighter aircraft to Iran.