Ali Akbar Velayati, an international adviser to the Leader of the Islamic Revolution, ruled out the possibility of negotiations between Tehran and Washington and said engaging in talks with the US is tantamount to surrender.

In a speech on Wednesday, Velayati deplored a recent letter signed by a number of Iranian reformist figures who demanded the country’s officials hold direct negotiations with the US to resolve the standoff over the nuclear deal known as the Joint Comprehensive Plan of Action (JCPOA).

“Those who are ingratiating themselves with Trump should know that if their expiration date comes, their own Green Cards and those of their children will be revoked by the United States,” he said.

“Negotiating with an individual who is not committed to any international agreements and does not even live up to pledges he has made to his allies would mean surrendering to the United States,” Velayati added.

Political activists who earlier signed the letter addressed to high-ranking Tehran officials on Sunday, warned against what they called the loss of an important opportunity.

The letter said that the talks could protect Iran's national interests and solve some of its problems.

Signatories included former Tehran mayor and leader of reformist faction the Construction Party, Gholamhossein Karbaschi, and former spokesman for the Foreign Ministry Hamid Assefi.

US President Donald Trump announced on May 8 that Washington was walking away from the nuclear agreement.

Trump also said he would reinstate US nuclear sanctions on Iran and impose “the highest level” of economic bans on the Islamic Republic.

Under the JCPOA, Iran undertook to put limits on its nuclear program in exchange for the removal of nuclear-related sanctions imposed against Tehran.