Blood from the victims of the Tunisian beach massacre turned the sand there the colour of terracotta, one traveller said.

Cal Sarwar flew back to Glasgow today after being in Sousse, where he was researching a book on Islamic terrorism in Africa.

The 50-year-old journalist from Falkirk had been staying in a neighbouring hotel when student Seifeddine Rezgui targeted western tourists on the beach area of the RIU Imperial Marhaba and the RIU Bellevue.

Mr Sarwar had been swimming in a pool just metres away from the scene, when he thought he heard fireworks.

But when he came up from under the water, he saw "pandemonium" with panicked holidaymakers running past.

He recalled: "I was in the pool, I wasn't on the beach, the pool is about 25 metres from the beach.

"I swim with earplugs in, so I was swimming away and I put my head up and saw people running past. The gunman had already run past by the time I put my head up out of the water.

"That was it, people screaming, pandemonium, chaos."

He added: "I was there writing my second book and it's ironic that this was happening."

Mr Sarwar said: "I heard something, I heard fireworks, from what I was told the guy had a Kalashnikov, he had reloaded several times.

"He went past me, I was told, I didn't see him.

"We went to the beach and it was a terracotta colour, the blood had mixed with the sand, it was just terracotta everywhere, like somebody had been painting. People were dragging people out of the water, it was quite a horrible scene

"When you see something like that you just don't expect it. I'm shocked and I will be for a long time."

He said there had been a heightened security presence in the area in the days before the attack, but said it had been scaled back just the day before

"Four days before the attack the whole atmosphere on the streets of Tunisia changed," Mr Sarwar said.

"Instead of taxis taking you right to your hotel doors they would drop you off at the gates, there were police blocks at the gates. But that security presence disappeared on Thursday afternoon, on Thursday afternoon we were allowed once again to take our taxis and get dropped off at the hotels again."

He added: "They were preparing for something, but I don't think they expected it to come from the water."

Sandra Clason, 53, said she and her partner James Erskine heard the gunfire from the attack, adding the hotel they were in was "too close for comfort".

Ms Clason, from Bo'ness, in West Lothian, told how they had been coming out of their hotel room when they heard the shots.

She said: "It was surreal, you hear it, and you know it's gunfire, but it was like fireworks. You could hear it getting closer, then nothing."

She added: "We were coming down but we were told to get back to the room. We were one of the lucky ones. We were too close for comfort."

The holidaymaker said: "I was quite frightened, I thought it was the end. We were just told to stay in the hotel, to stay close. So we din't go anywhere after, just stayed safe at the hotel."

Afterwards she said the atmosphere in the area was "quite glum".

She added: "It's very sad for the Tunisians because that will be the end of their economy basically."

Gail Merry, her husband Richard and their three children were also flying back from Tunisia today.

The family from Ayr had been staying at the Sahara Beach resort about 30 minutes away from Sousse when Mrs Merry received a news alert about the attack on her mobile phone.

She recalled: "We were sitting at the beach at our resort having our lunch when the news flash came through on my phone.

"I just handed my phone to my husband very slowly and said 'have a look at this' and he said 'let's just go back up to our room'."

For the rest of the holiday "apart from coming out from our room very briefly to eat, we just stayed in our room for the next two days."

Mrs Merry said she was relieved to be home, adding: "We had never been (to Tunisia) before, everything about the country was fantastic, we loved it, we had planned to go back annually. But there's not the security there that there should have been.

"We thought it was a brilliant place, but the security wasn't there. Considering what had happened we expected there to be some change, and nothing happened and that's put us off, we wouldn't go back."

Malcolm Lamont had been staying in Sousse and found out about the massacre on the television news in his hotel room, as he said there was "no information" locally.

But Mr Lamont, from Perth, said: "I wasn't worried, the hotel we were in was quite secure with guards on the gates, so we were told to stay in the hotel area.

"The resort after the incident was locked down, you couldn't move, taxis were all suspended, so it was total lock down until 48 hours after the incident."

He added it was "great" to be home "but sad in a way", saying: "It's sad for the locals, tourism is the main thing, so all the hotel staff are worried about their jobs."

Louise Markie, from Edinburgh, had been holidaying in another resort in Tunisia but said the atmosphere became "really sombre" after the attack in Sousse.

She said: "Our hotel was on the beach, and it was just the thought that it could happen to anybody."

Earlier, Scotland's First Minister Nicola Sturgeon chaired a second Scottish Government resilience (SGORR) meeting.

Deputy First Minister John Swinney, Justice Secretary Michael Matheson, External Affairs Minister Humza Yousaf, the Solicitor General and senior Police Scotland representatives also took part to discuss the continuing response to the attack and support for Scots affected.

Ms Sturgeon said: "I would like to offer my heartfelt sympathies to everyone who may have lost a loved one in this attack.

"We are prepared for the possibility that there may be Scottish victims among those who have lost their lives, but we have not yet received official confirmation of this.

"The threat level for the UK remains at severe and counter terrorism measures are in place to respond to this. The advice from Police Scotland is to stay vigilant and alert."

Jim and Ann McQuire, from Cumbernauld, North Lanarkshire, have been named on social media as having been killed in the attack, while Holly Graham, from Perth, has said she is concerned about her parents Billy and Lisa, who had been staying at one of the hotels attacked in Sousse.