"What is unseemly and unprecedented is for the podium of the State Department to be hijacked for political theatrics", he said.
Kerry has met with Iranian Former Minister Javad Zarif three or four times, while Trump took America out of the nuclear deal in May.
A spokesperson for Kerry rejected the criticism, saying in a statement that "no secrets were kept from this administration".
Pompeo contended on Friday: "You can't find precedent for this in United States history". It's inconsistent with what the foreign policy of the United States is, as directed by this president. "I wasn't in the meeting, but I am reasonably confident that [Kerry] was not there in support of U.S. policy with respect to the Islamic Republic of Iran, who, this week, fired kaytusha rockets toward United States rockets in Baghdad and took action against our consulate in Basra". With current brazen USA officials-who have unsheathed their swords against Iranians-what negotiations can we have?
He added: "Actively undermining US policy as a former secretary of state is literally unheard of".
This would mean that Kerry most probably did not coordinate his meetings with Trump administration officials.
He told radio host Hugh Hewitt that he has criticized the Trump administration in these discussions for not pursuing negotiations with Iran. I've also seen reports that he is apparently providing, according to reports, advice to the Iranian government.
Such meetings, between a private U.S. citizen and foreign officials, are not against the law and not necessarily inappropriate or a violation of federal regulations, but Trump and the GOP contend Kerry is trying to subvert the administration's hard line on Iran. "Stay away from negotiations John, you are hurting your country!" he said on May 8.
"The devil's always in the details", Rosenstein said.
When reports of Kerry's ex-officio contacts with Zarif first surfaced in May, Trump tweeted similar thoughts.
This bit of "shadow diplomacy" with the nation Kerry helped broker a nuclear deal with has enraged Trump, who tweeted about it on Thursday night.
In a September 9 interview with CNN's Fareed Zakaria, Kerry said the withdrawal was "a very risky and ill-advised move that is not based on any broad strategy that is drawing other countries to the table to be supportive of it".
"I think everybody in the world is talking about waiting out President Trump", Kerry said.
Trump accused Kerry Thursday of having "illegal meetings".