TEHRAN/LONDON – Two Iranian nationals have been sanctioned by Britain for their "hostile activity" on behalf of Iran, British Foreign Secretary Ed Miliband said in a statement on Monday.

They are now "subject to an immediate asset freeze, travel ban and director disqualification", Miliband said.

British Prime Minister Andy Burnham said on Monday that it was "highly likely" that Iran was involved in last month's incident at Royal Air Force (RAF) Fairford, a base hosting the US Air Force in southwest England, the BBC reported Monday.

"We recognize the United Kingdom's attribution of Iran's involvement in the incident at RAF Fairford on 27 September," according to a joint statement released on Monday by the foreign ministers of 29 countries, including Britain and the United States.

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On Sept 27, British police evacuated homes near RAF Fairford. Seven people have since been arrested on suspicion of explosives offenses and preparing an act of terror. The seven suspects, all in their 20s, have been released on bail.

The Iranian Foreign Ministry on Monday condemned Burnham's claim that a suspected plot targeting the RAF base was most probably "coordinated in Iran", calling Britain's accusation a "sordid plot to advance the anti-Iran campaign and evade accountability for Britain's participation in the US-Israeli military aggression against the Iranian nation".

It said London's use of terms such as "highly likely" and "almost certainly" to lend credibility to its accusations is a "conspicuous" attempt to evade responsibility for its "baseless" claims.

Six vessels hit in Strait of Hormuz

Multiple advisories issued by the UK Maritime Trade Operations on Monday and Sunday indicated that six vessels came under attack on Sunday in the Strait of Hormuz and adjacent waters of the Gulf of Oman.

Within the Strait of Hormuz, advisories 164-26 and 166-26 each reported an outbound tanker struck by an unknown projectile.

Advisories 168-26 and 169-26 reported attacks on a product tanker and a crude oil tanker, respectively, both of which were transiting outbound through the strait when struck by unknown projectiles.

Advisory 167-26 recorded an inbound container vessel struck by an unknown projectile while transiting the strait.

Update 001 to advisory 165-26 reported that a tanker near Oman's Sohar anchorage, in the Gulf of Oman close to the eastern approach to the Strait of Hormuz, was attacked by an unmanned aerial vehicle. Local authorities assisted with the evacuation of the crew.

Meanwhile, the navy of Iran's Islamic Revolutionary Guard Corps (IRGC) said on Monday that its forces hit another "violating" supertanker in the Strait of Hormuz earlier in the day.

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In a statement published on the IRGC's official news outlet Sepah News, the navy said the oil tanker, which had turned off its navigation system and sought to exit the strait while disregarding warnings from the Iranian naval forces, was set on fire following the strike.

It added the vessel was the third "violating" supertanker within the past two days to have suffered an explosion while attempting to "disrupt order and security" in the waterway.

Tensions between the United States and Iran over control of the Strait of Hormuz have escalated in recent weeks. Since late September, attacks on shipping in and around the strait have increased markedly, with casualties mounting.