Strained relations between Washington and Tehran got worse last month after the US parked a carrier strike group in the Arabian Sea and built up its presence in the Middle East while accusing Iran of involvement in the sabotage of four tankers off the coast of the United Arab Emirates.

Iranian Air Defence Force commander Brig. Gen. Alireza Sabahifard has urged Tehran's adversaries to keep their distance from the country's frontiers.

"We are warning the enemy: there is no safe zone for extraterritorial military aircraft in Iranian skies... Even approaching Iran's borders would be met with a strong response. Thus, I advise you to move as much away [from Iran's borders] as you can," the commander said, as quoted by PressTV.

Saying that any acts of aggression against Iran would 'bring regret' to the enemy, Sabahifard boasted that the US military's apparent decision to keep a safe distance of 200 nautical miles from the Strait of Hormuz waterway was the result of Iran's effective deterrent capabilities.

© AP Photo / Iranian Defense Ministry This photo released by the official website of the Iranian Defense Ministry on Sunday, June 9, 2019, shows the Khordad 15, a new surface-to-air missile battery at an undisclosed location in Iran

Commenting on US policy toward his country, Sabahifard urged his fellow countrymen and women not to give in to the various pressures.

"The enemy has imposed political, economic and cultural pressures on Iran, which have caused some troubles for the Iranian nation, but we should know that the costs of surrender are much higher than resistance," Sabahifard said.

According to the commander, the US expansion of its military power in West Asia and the Persian Gulf while calling for negotiations demonstrates the "unreliability" and "instability" of US diplomacy.

Last month, soon after scrapping sanctions waivers for multiple major importers of Iranian crude oil, the US deployed the USS Abraham Lincoln aircraft carrier, a complement of B-52 strategic bombers, Patriot missile defence batteries, fighters, an amphibious landing ship and hundreds of fresh troops to the Middle East, citing concerns about possible attacks by Iran or its proxies against the US and its allies.

On May 12, after the US deployment, four commercial tankers docked off the coast of the United Arab Emirates were struck in an apparent sabotage attack which Abu Dhabi investigators said was carried out by trained divers. The UAE concluded that the sabotage was likely the work of a "state actor," but did not point the finger directly at any country. US officials, meanwhile, accused Iran directly. In late May, Trump National Security Adviser John Bolton said it was "clear" that Iran was "almost certainly" responsible for the sabotage, but provided no evidence to back up the claim.

© Sputnik / Brian M. Wilbur June 1, 2019 file photo, the USS Abraham Lincoln carrier and a U.S. Air Force B-52H Stratofortress, conduct joint exercises in the U.S. Central Command area of responsibility in Arabian sea

Iran dismissed the charges as "ridiculous," and alleged that the sabotage attacks were part of alleged plans by the anti-Iran "B-Team" (a reference to Mr. Bolton, Israeli Prime Minister Benjamin Netanyahu, Saudi Crown Prince Mohammed Bin Salman and Emirati Crown Prince Mohammed Bin Zayed) to start a conflagration with Tehran.

On Thursday, as Japanese Prime Minister Shinzo Abe met with Iranian officials during the second day of his official visit to Tehran, two more tankers carrying "Japan-related cargo" were crippled in an apparent attack in the Strait of Hormuz, about 14 nautical miles off Iran's coast. Unnamed US defence officials accused Iran of responsibility for the attack, while Iranian Foreign Minister Mohammad Javad Zarif called the timing of the event beyond "suspicious" amid Abe's visit.