U.K. Foreign Secretary Boris Johnson | Christophe Petit Tesson/EPA Boris Johnson calls US plan for new Iran deal ‘very difficult’ UK foreign secretary reacts to a 12-point list of demands formulated by his US counterpart Mike Pompeo.

British Foreign Secretary Boris Johnson lashed out against U.S. plans of negotiating a new "jumbo" agreement with Iran Monday, saying such a negotiation would be "very, very difficult."

Johnson, who spoke to journalists in Buenos Aires on the sidelines of the G20 foreign ministers’ meeting, was reacting to a 12-point list of demands formulated by his U.S. counterpart Mike Pompeo earlier today. These include transparency and access for the International Atomic Energy Agency; the release of Americans held in Iran; an end to funding groups labeled as terrorist organizations by the U.S. and the cessation of other destabilizing activities in the region.

"The prospect of a new jumbo Iran treaty is going to be very, very difficult," Johnson said, according to the Guardian. "I think if you try now to fold all those issues — the ballistic missiles, Iran’s misbehavior, Iran’s disruptive activity in the region and the nuclear question — if you try to fold all those in to a giant negotiation, a new jumbo Iran negotiation, a new treaty — that’s what seems to be envisaged — I don’t see that being very easy to achieve, in anything like a reasonable timetable."

Pompeo has also threatened to impose “the strongest sanctions in history” on Tehran if it doesn't comply with the U.S. demands.

Johnson said the Joint Comprehensive Plan Of Action (JCPOA), from which U.S. President Donald Trump has withdrawn, is a good deal.

"The advantage of the JCPOA was that it had a very clear objective. It protected the world from an Iranian nuclear bomb, and in return it gave the Iranians some recognizable economic benefits. That was at the core of it. The Americans have walked away from that," he said.