President Barack Obama and Iran’s foreign minister shook hands when they ran into one another on the sidelines of the U.N. General Assembly in New York.

Foreign Minister Mohammad Javad Zarif came upon Obama “accidentally” and the two shook hands, according to a report Tuesday by Iran’s official IRNA agency.

A White House official, speaking on grounds of anonymity because the official was not authorized to speak publicly, confirmed Tuesday that “there was a brief interaction at the luncheon, where they shook hands.”

It represented the first handshake between an American president and Iran’s top diplomat since the 1979 Islamic Revolution ousted a pro-Western monarchy in Iran. The two countries have had no diplomatic relations since then.

Obama and Iranian President Hassan Rouhani spoke over the phone as Rouhani was leaving the U.N. in 2013 after his presidential debut at the General Assembly.

The IRNA report insisted the encounter was not planned. Iranian state TV said it transpired in “less than a minute” and that the U.S. Secretary of State John Kerry also introduced two of Zarif’s deputies who were there to Obama.

But Iranian hard-liners appeared bothered by the handshake.

“The foreign minister (Zarif) has committed a very bad action and he has to apologize to the great Iranian nation,” Mansour Haghighatpour, a member of parliament’s committee on national security and foreign policy, told the semi-official Fars news agency.

His committee colleague, Mohammad Hassan Asafari told The Associated Press that there should be an “investigation to see what the case was.”

Others speculated whether the handshake signaled better ties.

Maybe the “Islamic Republic intended to convey … that we are ready to begin a new chapter” with Washington, said lawmaker Mehrdad Lahouti.

Another lawmaker, Aboozar Nadimi disagreed, saying a “greeting like this does not mean it will lead to a deep, active and permanent relationship.”

(AP)