The US Federal Aviation Administration (FAA) has issued an advisory to all commercial carriers active in the overwater airspace above the Persian Gulf and the Gulf of Oman to exercise caution given heightened tensions between the United States and Iran.

According to the notice dated May 16, the FAA said affected Flight Informationa Regions (FIR) include parts of the Tehran FIR (OIIX), the Baghdad FIR (ORBB), Kuwait FIR (OKAC), Jeddah FIR (OEJD), Bahrain FIR (OBBB), Emirates FIR (OMAE), and Muscat FIR (OOMM).

"Exercise caution during flight operations due to the possibility of interruptions to international air traffic due to heightened military activities and increased political tensions in the region," it said.

Tensions in the Middle East have grown over the past few days following attacks on Saudi oil facilities and tankers by Yemen-based Houthi rebels, said to be Iranian proxies, using a combination of drones and rockets. Coupled with that was an attempted rocket attack on the US Embassy in Baghdad on Sunday, May 19, for which US Secretary of State Mike Pompeo initially blamed Iranian militants. US President Donald Trump subsequently threatened the regime in Tehran.

"If Iran wants to fight, that will [be] the official end of Iran. Never threaten the United States again," he tweeted.

Iran has dismissed Washington's allegations that there had been "imminent threats" from Tehran while accusing the US of an "unacceptable" escalation in tensions.