The United States and Arab allies launched strikes from the air and sea against Islamic State militants in Syria on Tuesday, opening a new front in the battle against the brutal jihadist group.
The US Central Command said in a statement that Bahrain, Jordan, Saudi Arabia, Qatar and the United Arab Emirates had joined Washington in carrying out the strikes.
"Using a mix of fighter, bombers, remotely piloted aircraft and Tomahawk Land Attack Missiles" the coalition conducted 14 strikes against IS targets in Syria, it said.
The strikes "destroyed or damaged" multiple targets in the jihadists' northern stronghold and near the border with Iraq including IS fighter positions, training compounds, command centres and armed vehicles.
The Syrian Observatory for Human Rights monitoring group meanwhile said US-led air strikes in western Aleppo province had killed 30 Al-Qaeda militants.
The US-led air assault in Syria marked a turning point in the war against the IS group, which has seized swathes of territory in Iraq and Syria and declared an Islamic "caliphate".
Washington had been reluctant to intervene in Syria's raging civil war, but was jolted into action as the jihadists captured more territory and committed widespread atrocities, including the on-camera beheadings of three Western hostages.
Tomahawks launched from warships
IS militants have warned the US-led campaign would be met with a harsh response and an IS-linked Algerian group on Monday threatened to kill a French hostage within 24 hours if Paris did not end its participation in air strikes in Iraq.
Washington said the strikes from the sea were carried put from US warships operating in the Red Sea and the Gulf and that 47 Tomahawks were fired.
Fighter jets, bombers and remotely controlled aircraft were used for the air strikes, which the five Arab nations "participated in or supported".
"All aircraft safely exited the strike areas," it said, adding that four air strikes were also conducted Monday in neighbouring Iraq, bringing the total number of US raids in that country to 194.
It said eight strikes were also carried out on a group of "seasoned Al-Qaeda" veterans west of Syria's second city Aleppo to disrupt an "imminent attack plotting against the United States and Western interests".
Jordanian government spokesman Mohammad Al-Momani told AFP the country's warplanes had taken part in strikes against IS in Syria and Iraq as "part of our efforts to defeat terrorism in its strongholds".
The Syrian Observatory for Human Rights, a Britain-based monitoring group, said its sources had reported numerous strikes in the northern Raqa province and near the Iraqi border. At least 20 militants were killed in two positions alone, it said.
Activists against President Bashar al-Assad's regime on the ground in Syria said the strikes had been targeted precisely and did not seem to have caused major civilian casualties.
"They are accurate but they were fierce, in comparison to those that were being carried out by the Assad regime," activist Assi al-Hussein, who is in the town of Albu Kamal on the Iraqi border, told AFP via the Internet.
Abu Yusef, an activist in Raqa, said one of the strikes had hit the ex-governorate building, which IS has used as its headquarters for many months.
"The strike on the governorate building caused a big fire and explosions. We suspect it is because it was being used as a weapons depot," the activist said.
The new strikes came less than two weeks after US President Barack Obama warned that he had approved an expansion of the campaign against the IS group to include action in Syria.
Damascus said that it had been informed by Washington of the air raids prior to the action on its soil.
Syria's opposition National Coalition welcomed the new strikes, but urged sustained pressure on Assad's government.
France vows no hostage talks
"Tonight, the international community has joined our fight against ISIS in Syria," Coalition president Hadi al-Bahra said, using an alternative acronym for the jihadist group.
"We are calling on all our partners to maintain pressure on the Assad regime," Bahra said. "This war cannot be won by military means alone."
The raids came hours after Algerian group Jund al-Khilifa (Soldiers of the Caliphate) posted a video showing the white-haired and bespectacled French hostage, Herve Pierre Gourdel, squatting on the ground flanked by two hooded men clutching Kalashnikov assault rifles.
In the footage, confirmed by Paris as authentic, the group gave France 24 hours to halt its air strikes in Iraq, saying that it was responding to an IS call to kill Westerners whose nations are among 50 countries that have joined the campaign to battle the jihadist group.
French Prime Minister Manuel Valls told French radio there would be "no discussion, no negotiation" with the Algerian group and stressed Paris would continue its air strikes.
In a separate incident on Tuesday, Israel shot down a Syrian fighter jet over the Golan Heights, indicating that it had crossed a ceasefire line into the Israeli-occupied sector.
Israeli army radio said it was apparently a MiG-21 fighter jet which was shot down by a surface-to-air Patriot missile, with the wreckage landing on the Syrian-controlled side of the plateau.
