US-Iran tension: Tehran says it's in charge of security of Strait of Hormuz

Iran said on Friday it was responsible for maintaining the security of the Strait of Hormuz in the Gulf, state radio reported, adding that blaming Tehran for attacks on two oil tankers in the Gulf of Oman was alarming.

"We are responsible for ensuring the security of the Strait and we have rescued the crew of those attacked tankers in the shortest possible time," Radio quoted Foreign Ministry spokesman Abbas Mousavi as saying.

"Obviously, accusing Iran for such a suspicious and unfortunate incident is the simplest and the most convenient way for (US Secretary of State Mike) Pompeo and other US officials. These accusations are alarming."

The United States blamed Iran for attacks on two oil tankers in the Gulf of Oman on Thursday that drove up oil prices and raised concern about a new US-Iranian confrontation.

It was not immediately clear what caused the explosions that forced the crews to abandon ship and leave both the Norwegian-owned Front Altair and Japanese-owned Kokuka Courageous adrift in waters between Gulf Arab states and Iran.

The blasts, south of the Strait of Hormuz, followed last month's sabotage attacks on vessels off the Fujairah emirate, one of the world's largest bunkering hubs. Iran has distanced itself from the attacks.

Almost a fifth of the world's oil passes through the Strait - some 17.2 million barrels per day (bpd). Consumption was about 100 million bpd in 2017, data from analytics firm Vortexa showed.

Brent crude futures rose 0.6 per cent to $61.69 per barrel in Asian trade on Friday, having gained 2.2 per cent the previous day, though at one point they had surged as much as 4.5 per cent in the wake of the attacks.

Iran's key regional rival Saudi Arabia said that Riyadh was committed to providing reliable oil supplies to global markets.

One source said the blast on the Front Altair, which caught fire and sent a huge plume of smoke into the air, may have been caused by a magnetic mine. The firm that chartered the Kokuka Courageous tanker said it was hit by a suspected torpedo, but a person with knowledge of the matter said torpedoes were not used.

The US military released a video late on Thursday that it said showed Iran's Revolutionary Guard (IRGC) removing an unexploded mine from the side of the Japanese-owned oil tanker.

The US military's Central Command also released photographs showing the apparent mine, which attaches to the side of a ship magnetically, before it was removed later in the day.

Tension between Iran and the United States has risen since May last year, when US President Donald Trump pulled out of a 2015 nuclear deal between Iran and major powers that aimed to curb Tehran's nuclear ambitions in exchange for sanctions relief.

Iran has repeatedly warned it would block the Strait of Hormuz if it cannot sell its oil because of US sanctions.

Tensions have increased further since Trump reimposed sanctions on Iran and acted at the beginning of May to force Iran's oil customers to slash their imports to zero or face draconian US financial sanctions.

Iran's oil exports, its economy's lifeblood, have dropped to about 400,000 bpd in May from 2.5 million bpd in April last year.

Meeting on Friday on the sidelines of a regional summit in Kyrgyzstan, Chinese President Xi Jinping told Iran's President Hassan Rouhani on Friday that China will promote steady development of ties with Iran no matter how the situation changes, the official Xinhua news agency reported.