U.S. President Donald Trump and North Korean leader Kim Jong-un walk together before a working lunch during their summit at the Capella Hotel on the resort island of Sentosa, Singapore, June 12. / Reuters

By Park Si-soo

Two longtime foes ― the United States and North Korea ― appear to be getting closer after the historic first meeting of their leaders in Singapore on Tuesday.

After the summit, U.S. President Donald Trump started promoting his newly forged bromance with North Korean leader Kim Jong-un, praising Kim as "strong," "funny" and "smart." And if silence means OK, it seems that Kim is also enjoying the afterglow.

But Iran has thrown a spanner into the works.

Just hours after the historic meeting ended, the Middle East country jumped into the ring and warned the North's leader: "Don't trust Trump."

Tehran cited its own experience in offering the advice to Kim a month after Washington withdrew from a similar deal with Iran.

"We don't know what type of person the North Korean leader is negotiating with," Iranian government spokesman Mohammad Bagher Nobakht was quoted as saying by the IRNA news agency, Tuesday. "It is not clear that he would not cancel the agreement before returning home."

The comment came only hours after Trump and Kim signed a historic denuclearization agreement.

The spokesman questioned Trump's credibility: "This man does not represent the American people, and they will surely distance themselves from him at the next elections."

Iranian foreign ministry spokesman Bahram Qasemi threw his weight behind the warning, advising the North to "exercise complete vigilance" in negotiations with Trump.

"We are not optimistic about these talks ... The United States, especially Mr. Trump, has undermined international agreements and has unilaterally withdrawn from them," Reuters quoted Qasemi as saying.