FILE- In this July 21, 2019 file photo, a speedboat of the Iran's Revolutionary Guard moves around a British-flagged oil tanker Stena Impero, which was seized on Friday by the Guard, in the Iranian port of Bandar Abbas. The assault on the beating heart of Saudi Arabia’s vast oil empire follows a new and dangerous pattern that’s emerged across the Persian Gulf this summer of precise attacks that leave few obvious clues of who launched them. (Hasan Shirvani/Mizan News Agency via AP, File)

TEHRAN, Iran (AP) — Iran warned the U.S. that any action taken against it following an attack on Saudi oil installations will “immediately” be met with a response from Tehran, its state-run news agency reported Wednesday, further raising Mideast tensions.

Iran’s president and foreign minister also may skip next week’s high-level meetings at the United Nations as the U.S. has yet to issue them visas, IRNA reported.

The U.N. meeting had been considered as an opportunity for direct talks between Iranian President Hassan Rouhani and President Donald Trump amid a summer of heightened tensions and attacks in the wake of America’s unilateral withdraw from Iran’s nuclear deal with world powers a year ago.

However, the recent attack in Saudi Arabia and hardening comments from Iran suggest such talks are increasingly unlikely.

Iran sent a note through Swiss diplomats in Tehran on Monday, reiterating that Tehran denies being involved in the Saudi attack, IRNA reported. The Swiss have looked after American interests in Tehran for decades.

“If any action takes place against Iran, the action will be faced by Iran’s answer immediately,” IRNA quoted the note as saying. It added that Iran’s response wouldn’t be limited to the source of the threat, without elaborating.

IRNA separately reported Wednesday that Iran’s first delegation for the annual U.N. event had not left Iran due to not having visas. Foreign Minister Mohammad Javad Zarif was to travel to New York on Friday, with Rouhani following behind Monday, according to the agency.

As the host of the U.N.’s headquarters, the U.S. is mandated to offer world leaders and diplomats visas to attend meetings there. But as tensions have risen, the U.S. has put increasing restrictions on Iranians like Zarif.

The U.S. State Department did not immediately respond to a request for comment Wednesday.

U.S. Secretary of State Mike Pompeo is traveling to Saudi Arabia for meetings after Saturday’s attack on a Saudi oil field and the world’s largest crude oil processing plant. Saudi officials separately planned to share information about the weapons used in the attack they allege are Iranian.