Daish blasts in Syria regime heartland kill more than 148

Seven near-simultaneous explosions targeted bus stations, hospitals and other civilian sites in the seaside cities of Jableh and Tartus, which until now had been relatively insulated from Syria's five-year civil war.

The unprecedented attacks on strongholds of President Bashar al-Assad's regime came as IS faces mounting pressure in both Syria and Iraq, where Baghdad's forces on Monday launched a major offensive to retake the jihadist-held city of Fallujah.

A hundred people were killed in Jableh and another 48 in Tartus to the south, at least eight of them children, according to the Syrian Observatory for Human Rights monitoring group.

Observatory head Rami Abdel Rahman said they were "without a doubt the deadliest attacks" on the two cities since the start of the war.

IS claimed the blasts via its Amaq news agency, saying its fighters had attacked "Alawite gatherings" in Jableh and Tartus, referring to the minority sect from which Assad hails.

IS is not known to have a presence in Syria's coastal provinces, where its jihadist rival and Al-Qaeda's local branch Al-Nusra Front is much more prominent.

But IS is notorious for using deadly sleeper cells to attack its enemies.

"I'm shocked, this is the first time I hear sounds like this," said Mohsen Zayyoud, a 22-year-old university student in Jableh.

'In the heart of the battle'

"I thought the war was over and that I could walk safely. But I was surprised to see that we're still in the heart of the battle," he said.

In Tartus a 42-year-old bank employee was just as stunned.

"It's the first time we hear explosions in Tartus, and the first time we see dead people or body parts here," Shady Osman said.

Jableh lies in Latakia province, while Tartus is the capital of the adjacent governorate of the same name.

Both cities have remained relatively secure even as the war has raged in Latakia province's rural northeast and throughout the country.

State media earlier said 78 people -- 45 in Jableh and 33 in Tartus -- were killed in the bombings.

The attacks began at 9:00 am local time (0600 GMT) with three explosions at a busy bus station in Tartus, where regime ally Russia has long maintained a naval facility.

The Observatory said one car bomb detonated first, and as people began to flock to the site two suicide bombers detonated explosive belts.

A police source in the city confirmed a car bomb had hit the entrance to the station and two suicide bombers attacked inside.

State television broadcast footage of the damaged station, where charred mini-buses lay on their sides while others were still ablaze.

Approximately 15 minutes after the Tartus blasts, the explosions began in Jableh, 60 miles (40 kilometres) to the north.

Blast inside hospital

The Observatory said four blasts -- one car bomb and three suicide attackers -- targeted a bus station, a hospital, and a power station there.

One attacker detonated explosives inside the emergency room of the state-run hospital after carrying victims of the first attack there, the monitor said.

A police officer told AFP a car bomb also targeted the Asaad hospital in the city.

A Kremlin spokesman condemned the attacks, saying they "demonstrate yet again how fragile the situation is in Syria and the need to take energetic measures to relaunch peace talks."

A spokesman for the French foreign ministry also slammed the bombings as "heinous".

World powers have struggled to rekindle UN-brokered peace negotiations which fizzled in April when Syria's opposition walked away in frustration at stalling progress on the country's dire humanitarian situation.

Syria's conflict has evolved from a popular uprising to a multi-faceted war that has killed more than 270,000 people and displaced millions.

IS seized control of large parts of Syria and Iraq in mid-2014, declaring an Islamic "caliphate" and spreading its influence.

The group has claimed deadly attacks in the West and throughout the Middle East, including twin bombings on military forces in Yemen's second city of Aden on Monday that killed at least 41 people.