Iran has no intention of making or using nuclear weapon but it will not repeat its "bitter experience" of negotiating with the United States, Iran’s Supreme Leader Ayatollah Ali Khamenei told Japanese Prime Minister Shinzo Abe in Tehran on Thursday.

"I do not see Trump worthy of any message exchange, and I do not have any reply for him now or in future," Fars news agency quoted Khamenei as saying.

Khamenei also said Trump's promise not to seek regime change in Iran was "a lie," adding that he did not believe Washington's offer of "honest negotiations" with Tehran.

Khamenei's comment, a reiteration of Iran’s stance, comes at a time of increased U.S.-Iranian tension, a year after Washington abandoned an agreement between Iran and world powers to curb its nuclear program in exchange for the lifting of international financial sanctions.

Abe was carrying a message to Iranian leaders from U.S. President Donald Trump.

"Supreme Leader Khamenei made a comment that the country will not and should not make, hold or use nuclear weapons, and that it has no such intentions," Abe told reporters in Tehran following a meeting with Khamenei.

"Today, I met Supreme Leader Khamenei and heard his belief in peace. I regard this highly as a major progress toward this region's peace and stability," said Abe, the first-ever Japanese prime minister to hold talks with Khamenei.

Abe’s comment was broadcast on Japanese public broadcaster NHK.

On Wednesday, Abe also met Iranian President Hassan Rouhani. He warned of unintended clashes in the crisis-hit Middle East after the meeting.

He said: "Armed conflict needs to be prevented at all costs. Peace and stability in the Middle East is indispensable not only for this region but for global prosperity. No one is hoping for war."

While Abe did not mention Japan’s currently suspended purchases of Iranian oil, Rouhani said that Japan wants to keep buying Iranian oil.

"In our meeting, Mr. Abe said that Japan was interested in continuing buying Iran’s oil," Rouhani told a joint news conference with Abe, broadcast live on state TV.

Japan is in a unique position to act as a mediator as the U.S. ally has long maintained close ties with Iran.

The Iranian side has said Tehran would ask Tokyo to mediate between it and Washington to ease oil sanctions on Iran.

"America should either lift the unjust oil sanctions or extend the waivers or suspend them," one senior official said.

To slash Iran’s oil exports, Washington has revoked waivers since May that had allowed some countries, including Japan, to continue buying Iranian crude and has effectively ordered countries to stop purchasing Iranian oil or face sanctions of their own.

Despite pushing for imports to continue, Japan has stopped importing oil from Iran for now to avoid U.S. sanctions.

On a visit to Japan last month, Trump welcomed Abe's help in dealing with Iran, highlighting what he called the "very good relationship" between Tokyo and Tehran.