US officials said Monday that initial assessments of an incident over the weekend in which four oil tankers were damaged by explosions in Emirati waters point to Iranian involvement.

Four oil tankers — two Saudi, one Emirati and one Norwegian — off the coast of the Fujairah, in the United Arab Emirates, suffered on Sunday what the UAE Foreign Ministry called "sabotage operations." The explosion blew a five-to-10 foot hole in each ship near or just below the water line, a US military team told AP Monday.

"Iranian or Iranian-backed proxies" are believed to be behind the attack, according to US officials.

Fujairah is Abu Dhabi's only major port on the Arabian Sea. In the event of war, Tehran has already threatened to close the Strait of Hormuz, immediately strangling 20% of world seaborne oil trade, making Fujairah of great strategic importance.

While the explosions weakened the structures of the four vessels, none suffered any injuries or deaths and no oil was leaked from the ships, Sputnik noted.

Iranian Foreign Ministry spokesman Abbas Mousavi earlier on Monday called the incident "worrisome and dreadful," adamantly denying Tehran's involvement.

"Such incidents have a negative impact on maritime transportation security," Mousavi said, decrying the incident whether it was "orchestrated by ill-wishers" or "adventurism by foreigners."

The US has deployed extensive military forces to the region in recent days, with nuclear-capable B-52 bombers arriving in Qatar and the aircraft carrier USS Abraham Lincoln sailing into the region as well. Last month, US President Donald Trump declared Iran's Revolutionary Guard Corps (IRGC) a terrorist entity, claiming the group was responsible for US servicemember deaths in Syria and Iraq.

In early August 1964, a similar incident occurred in the Gulf of Tonkin, off the coast of North Vietnam. Amid another massive US military buildup off the coast of a country Washington was threatening with military action, reports of attacks on US ships by North Vietnamese gunboats led to the US Congress authorizing the use of military force against Hanoi in response to the provocations.

However, it was later revealed that no such attack ever happened. A US National Security Agency internal memo declassified in 2005 revealed that no North Vietnamese ships were present at that time.