Marie Colvin was a distinguished foreign correspondent for the Sunday Times. She was originally from New York State in the US but had been based in London for many years.
Speaking to the BBC from Homs on Tuesday, she said she had seen "sickening" scenes, and watched a baby die from shrapnel injuries.
She had worked in conflict zones from Kosovo to Chechnya, and across the Arab world.
She was injured while reporting from the rebel-held northern region of Sri Lanka in 2001 and lost the sight in her left eye.
Speaking in 2010 at a service remembering journalists killed in conflict, she said that war reporting must continue, despite the dangers.
"Our mission is to report these horrors of war with accuracy and without prejudice," she said.
"We always have to ask ourselves whether the level of risk is worth the story."
Marie Colvin, who was 56 and a Yale graduate, was known for her personal style of war reporting and had frequently been the lone journalist in areas of high risk.
She won many awards for her work, including Foreign Reporter of the Year at the British Press Awards in 2010.
Paying tribute to Marie Colvin, the editor of the Sunday Times, John Witherow, said she was an "extraordinary figure" in the life of the paper, driven by a passion to cover wars in the belief that what she did mattered.
Her thoughts were always with the victims of violence, he said.
He added that 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 Colvin's report from Homsappeared on the front page of the most recent edition of the Sunday Times. Referring to the article in an email to the BBC's Middle East Editor, Jeremy Bowen, on Monday night, Marie Colvin wrote that she thought the piece "was one of those we got into journalism for".
"They are killing with impunity here, it is sickening and anger-making," she wrote.
Writing to a friend on Facebook the night before she was killed, she joked that reports of her survival "may be exaggerated".
She said of Baba Amr that she could not understand "how the world can stand by and I should be hardened by now.
"Feeling helpless. As well as cold! Will keep trying to get out the information."
Her mother told journalists Ms Colvin's legacy was: "Be passionate and be involved in what you believe in. And do it as thoroughly and honestly and fearlessly as you can."
The French photojournalist Remi Ochlik was born in 1983 in Lorraine.
After studying photography in Paris he began his career covering conflict zones with a trip to Haiti in 2004.
In 2005 he founded a photographic agency, IP3 Press, in Paris, with two fellow photographers.
He covered the war in the Democratic Republic of Congo in 2008, and was back in Haiti in 2010, photographing the cholera epidemic and presidential elections.
In 2011 he covered the Arab Spring revolutions in Tunisia and Egypt and the war in Libya.
He won a first prize in the 2012 World Press Photo contest forthis imageof a rebel fighter in Libya.
The two journalists who have been killed in Homs were both veterans of war zones across the world despite their differing ages.