Three blasts rocked the popular holiday resort of Marmaris in the south of the country, while one bomb exploded on a bus in Istanbul.

Witnesses in Marmaris, where the Britons were injured, said that a bomb had been left under a seat in the bus. The first blast, shortly before midnight local time, was followed about 45 minutes later by an explosion near the city’s harbour and a third in a residential area, it was reported. No one was thought to be injured in the last two blasts.

Turkish television said that at least 27 were injured during the four blasts. According to reports, the bomb in Istanbul had been left near a school in the Bagcilar district of the city at about 9.30pm local time. At least six people were hurt.

Of the ten Britons injured in Marmaris, six were taken to the Abu Hetman Hospital. Four are in a serious condition, according to the Foreign and Commonwealth Office.

Another four were taken to the Caria Hospital. A spokeswoman there said that all of them had suffered burns and shrapnel injuries to their “lower extremities” when the bomb exploded on the bus, which was outside a McDonald’s restaurant.

She said that a couple from Coventry, aged 38 and 44, had suffered minor injuries while a 13-year-old girl and a 73-year-old woman had undergone surgery.

The hospital spokeswoman added: “None of them has life-threatening injuries, but of course they are terribly shocked and two have got particularly nasty injuries to their legs.”

Rob Laughton and his wife, Susan, who live in West London, were having dinner at the Rover’s Return restaurant when the bus bomb exploded. The couple ran out and saw bodies lying around the vehicle.

Mr Laughton, 41, an assistant operations manager for a catering firm, said: “We heard this almighty explosion. We just saw the bus and bodies lying on the ground. We thought, we just don’t want to be here. We just ran away." Danielle Pearson, a Scottish holidaymaker, said that the streets of the resort had been busy. She said: “We heard one of the bombs and it sounded just like a gunshot. The bus had exploded outside a McDonald’s restaurant. We saw its remains: it had been ripped apart. Ambulances and police cars were going everywhere. The streets were really busy, with people running everywhere. Before the explosions people were being typical holidaymakers and just enjoying themselves.”

Michael Grant, 39, who has been living in Marmaris for 20 years, said: “I heard the explosions. They were very loud, extremely loud, and then there were police and ambulances going to the scene. My housemate, Debra Lewis, and I could see people running from from the area and police and ambulance crews.

“What we have heard from people coming from the area of the blasts is that there were three explosions at about 1am local time and it was supposed to be an attack by the PKK, the Kurdish national party.”

Jill Thornton, of Consett, Co Durham, said that her son, Daniel, 19, had seen the aftermath of one bomb. He had told her that another blast took place on a bus travelling to Icmeler, a nearby fishing village.

No group had claimed responsibility last night for planting the bombs.

A spokeswoman for the Foreign Office said early this morning: “There have been three explosions in the resort of Marmaris, Turkey and ten British nationals have been injured and are in hospital. We have consular staff on the ground.

“We have no further details in terms on the cause of the explosions or the location,” the spokeswoman added.

Asked if the ten injured Britons were holidaymakers, she added: “I think that would be the assumption because it is a holiday resort but I would imagine there would be British nationals living in the area as well.”

The Foreign Office has issued a helpline number: 020-7008 0000.

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