TOKYO — Iran is pinning its hopes on the success of talks with the West about its nuclear program but has no plans to abandon a controversial reactor, its foreign minister said Wednesday.

Mohammad Javad Zarif made the comments as he ended an official visit to Tokyo which included talks with his Japanese counterpart Fumio Kishida and Prime Minister Shinzo Abe.

“We have based all of our calculations on the success of these negotiations,” Zarif told reporters.

“I think that’s a better option, for the negotiations to succeed. It’s a better option for everybody.”

Under a November interim deal, Iran agreed to roll back or freeze some nuclear activities for six months in exchange for modest sanctions relief and a promise by Western powers not to impose new restrictions on its hard-hit economy.

The West and Israel have long suspected Iran is pursuing a nuclear weapons capability alongside its civilian program, something Tehran denies.

Also Wednesday, US envoy Joseph Macmanus told the International Atomic Energy Agency’s 35-nation board Wednesday that Tehran must also fully cooperate with the IAEA in its probe of the weapons allegations.

He said clearing up suspicions that Iran worked on nuclear arms “will be critical” to any final accord meant to give Tehran full final sanctions relief.

Zarif said Iran would not shutter the unfinished Arak heavy water reactor, a concern to the West because Tehran could extract weapons-grade plutonium from its spent fuel if it also builds a reprocessing facility.

This would give it a second route to a nuclear bomb.

On Tuesday, Israeli prime Minister Benjamin Netanyahu said Iran’s refusal to shutter Arak showed it was covertly pursuing nuclear weapons.

Zarif said Arak was crucial for peaceful scientific pursuits, and insisted that “we are not going to close it.”

“We believe the solution is at hand,” he told a joint press conference with Kishida. “I am sure if the other sides comes with the same posture we will have a satisfactory conclusion within a short period of time.”

He praised Japan’s expertise in the nuclear field and said more investment in Iran’s atomic sector could serve as “a mutual confidence-building operation.”

“Japan can also be on the ground in Iran and see for itself that Iran’s program is nothing but peaceful,” he added.

Japan has been reducing Iranian oil imports despite energy shortfalls in the wake of the tsunami and nuclear incident three years ago, which forced Tokyo to turn to pricey fossil-fuel options to plug the energy gap.

Kishida said he had promised Japan’s help in trying to broker a deal between Tehran and world powers.

“I told the foreign minister that Japan, along with the international community, will actively engage in the process towards the final agreement,” he told reporters.

“The comprehensive solution to Iran’s nuclear issue is extremely important, not only for the Middle East, but also for the peace and stability of the world.”