In an alleged conspiracy foiled by US investigators, the pair spoke of hiring hitmen who would force Kyaw Moe Tun to resign or, if he refused, to kill him, officials said.

The pair "plotted to seriously injure or kill Myanmar's ambassador to the United Nations in a planned attack on a foreign official that was to take place on American soil," said Audrey Strauss, the US attorney for the southern district of New York.

Jacqueline Maguire, the acting assistant director of the US Federal Bureau of Investigation, said law enforcement acted "quickly and diligently" after learning of the potential assassination that was planned in Westchester County, a suburban area north of New York City where the ambassador lives.

The bureau received a tipoff on Tuesday, according to court documents.

"Our laws apply to everyone in our country, and these men will now face the consequences of allegedly breaking those laws," Maguire said in a statement.

Suspects Phyo Hein Htut, 28, and Ye Hein Zaw, 20, were being charged in a federal court in Westchester on counts for which they could be sentenced to up to five years in prison.

- Dealer tied to junta -

It remained unclear what, if any, connection the suspects had with the military junta, which on February 1 overthrew the elected government of Aung San Suu Kyi in the country earlier known as Burma.

Prosecutors said Phyo Hein Htut had been in touch with an arms dealer in Thailand who had dealings with the military in Myanmar. The two conversed by the video chat service FaceTime, while Phyo Hein Htut was inside Myanmar's UN mission in New York, a criminal complaint said.

The arms dealer spoke to Phyo Hein Htut about hiring assailants for the plot, which involved sabotaging the tires of the ambassador's car to force it to crash, the criminal complaint said.

The complaint included photos of what appeared to show $4,000 sent in July via the Zelle digital payment app from Ye Hein Zaw to Phyo Hein Htut, allegedly as an advance payment for the hit.

Kyaw Moe Tun made headlines after the coup by flashing the three-finger salute of democracy protesters from his UN chair as Myanmar's representative, brazenly defying the junta's insistence that he no longer represents the country.

He had told AFP on Wednesday that there was a threat against him and that he was being assigned additional security.

If there is evidence of official involvement in the purported plot, it would likely only further US efforts to pressure the junta to step down.

More than 900 people have died in Myanmar as the military seeks to crush protests against the coup, according to a local monitoring group.

Kyaw Moe Tun has repeatedly called for international intervention to help end unrest and reinstate Myanmar's civilian government.

In a letter this week, he called for a global arms embargo on the junta, which maintains relations notably with neighboring China.