Syria air strikes: US launches attack on Isis as jihadist group warns of retribution

Pentagon says strikes targeted areas including Isis stronghold Raqqa

The guided-missile cruiser USS Philippine Sea (CG 58) launching a Tomahawk cruise missile against Isis targets in Syria, as seen from the aircraft carrier USS George H.W. Bush (CVN 77) in the Arabian Gulf

The US military has launched its first air strikes against Isis militants in Syria supported by a coalition of five Arab states, the Pentagon confirmed on Tuesday.

Syrian state television reported on Tuesday that Washington informed Syria's United Nations envoy before the attacks began, quoting Syria's Foreign Ministry as the source. However, Syria did not formally consent to them taking place in its territory.

Here are the major developments so far:

• The wife of Alan Henning, the British aid worker being held by Isis, has received an audio message of her husband "pleading for his life".

• Isis has released a propaganda video showing British hostage John Cantlie deliver a scripted condemnation of the US.

• The Pentagon spokesman Rear Adm John Kirby said fighter jets, bombers and Tomahawk cruise missiles were fired from ships in the region during the strikes.

• Syrian Twitter user Abdulkader Hariri apparently live-tweeted the US attacks 30 minutes before the Pentagon broke the news.

• President Obama said the US launched strikes against the al-Qaeda linked Khorasan group, hours after the military confirmed it attacked a second terrorist group plotting an “imminent attack against America and Western interests” in Syria.

• Footage has emerged showing two Syrian pilots parachuting to the ground from their plane after it was shot down by an Israeli missile.

• David Cameron has confirmed his support for air strikes and said the UK will consider its response to tackling Isis.

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Britain was not involved in the strikes but the Ministry of Defence (MoD) said discussions on whether to join the strikes in Syria are “ongoing” and "no decision has been taken to our involvement".