Reuters: Sunday Times' journalist Marie Colvin and photographer Remi Ochlik killed in Homs

Reuters has reported that Sunday Times journalist Marie Colvin and French photographer Remi Ochlik were killed in the besieged Syrian city of Homs when shells hit the house they were staying in, according to opposition activists and witnesses.

A witness told Reuters by phone that shells hit the house where the journalists were staying and a rocket hit them as they were escaping.

The Daily Telegraph reports that the attack on the journalists has triggered suspicions that a makeshift media centre was deliberately targeted by regime forces.

Colvin reported on the shelling in Homs in a video for the BBC yesterday, in which she described the bloodshed as “absolutely sickening”.

Throughout her career Colvin has covered many conflicts , most recently Tunisia, Egypt and Libya in the Arab spring.

She also worked in Chechnya, Kosovo, Sierra Leone and Sri Lanka, where she was injured in an ambush by government soldiers.

Colvin once said of frontline war reporting: “Our mission is to report the horrors of war with accuracy and without prejudice”.

She has won the British Press Award for “Best Foreign Correspondent” twice, for her work in reporting the conflict in Yugoslavia, Iran, Sri Lanka and Zimbabwe; the International Women’s Media Foundation award for “Courage in Journalism” for her coverage of Kosovo and Chechnya, and the Foreign Press Association's Journalist of the Year award.

Channel 4 News' Jon Snow tweeted: "Assad's assassination of Marie Colvin:Utterly devastating: the most couragious journalist I ever knew and a wonderful reporter and writer."

Last night, Colvin described to Channel 4 News the "merciless" attacks on civilians surrounding her.

She said: "I think the sickening thing is the complete merciless nature. They're hitting civilian buildings mercilessly and without caring. The scale of it is just shocking."

The French television journalist, Gilles Jacquier, was killed in Homs on 11 January, while visiting the city on a government-organised trip.

Update: Sunday Times editor John Witherow said in a statement:

"I want to report with great shock the sad news of the death of Marie Colvin in Syria today. We have reliable reports that Marie was killed in Homs while covering the devastating bombardment by the Syrian army. She was with Paul Conroy, the freelance photographer, who was injured in the attack. We do not know the extent of his wounds but the early reports suggest he is not too seriously hurt. We are doing what we can to get him to safety and to recover Marie's body

"Marie was an extraordinary figure in the life of The Sunday Times, driven by a passion to cover wars in the belief that what she did mattered. She believed profoundly that reporting could curtail the excesses of brutal regimes and make the international community take notice. Above all, as we saw in her powerful report last weekend, her thoughts were with the victims of violence.

"Throughout her long career she took risks to fulfil this goal, including being badly injured in Sri Lanka. Nothing seemed to deter her. But she was much more than a war reporter. She was a woman with a tremendous joie de vivre, full of humour and mischief and surrounded by a large circle of friends, all of whom feared the consequences of her bravery.

"Marie was recruited to The Sunday Times more than a quarter of a century ago by David Blundy, her predecessor as Middle East correspondent, who was himself killed in El Salvador in 1989. It shows the risks that foreign correspondents are prepared to take in the pursuit of the truth.

"Marie will be missed sorely by all of us and her many friends."

Rupert Murdoch, owner of the Sunday Times, added: "Marie had fearlessly covered wars across the Middle East and south Asia for 25 years for The Sunday Times. She put her life in danger on many occasions because she was driven by a determination that the misdeeds of tyrants and the suffering of the victims did not go unreported. This was at great personal cost, including the loss of the sight in one eye while covering the civil war in Sri Lanka. This injury did not stop her from returning to even more dangerous assignments.

"Our immediate thoughts are with her family."

Michelle Stanistreet, NUJ general secretary, said: “We send our condolences to Marie’s family and the family of Remi Ochlik, also killed in the attack. Marie was an excellent reporter who said that her mission was ‘to report the horrors of war with accuracy and without prejudice’. She did that with bravery and grace. The unspeakable violence that the government of Syria is meting on its own people is something it does not want the eyes of the rest of the world to see. Marie and her colleagues knew they had to be there to shine a torch on such atrocities, with the consequent risk to their lives.”

The International Federation of Journalists is calling on the Syrian authorities to avoid indiscriminate attacks which risk costing lives of civilians, including journalists. This follows the Red Cross appeal to warring factions to cease fire so as to enable humanitarian assistance for the benefit of the civilian population.

"The Damascus government is persisting in its bloody policy of censorship and suppression of information,” Reporters Without Borders said. “It has decided to punish the entire population collectively and to use the most violent means to silence those journalists who witness its excesses.

“The international community can no longer remain passive in the face of the tragedy sweeping towns and cities that are the strongholds of pro-democracy protests.”

"Our colleagues Marie Colvin and Rémi Ochlik gave their lives to report a story of grave importance, a story the Syrian government has sought to choke off from rest of the world," said Committee to Protect Journalists deputy director Robert Mahoney. "The killing of these journalists, who were observers in a conflict zone, represents an unacceptable escalation in the price that local and international journalists are being forced to pay."

French president Nicolas Sarkozy described the deaths of the two journalists as an assassination, and said that the Assad era had to end."That's enough now," Sarkozy said. "This regime must go and there is no reason that Syrians don't have the right to live their lives and choose their destiny freely. If journalists were not there, the massacres would be a lot worse."

• Remi Ochlik won a 2012 World Press Photo award for an image from the conflict in Libya.
• BBC News is carrying tributes to Colvin.
• Marie Colvin's last article for the Sunday Times from Syria is outside the paywall.
  
• Pic: The Sunday Times