Marie Colvin, an American war reporter who took a break to participate in Malta's Middle Sea Race in 2004, was killed in the Syrian city of Homs this morning.

The reporter, who worked for Britain's Sunday Times, was killed along with   French photographer Remi Ochlik when the house where they were staying was shelled by pro-government forces.

A Syrian opposition activist told AFP two Western journalists were killed and three wounded when forces loyal to Bashar al-Assad's regime shelled a makeshift media centre in the Baba Amr district of Homs.

"Homs is a very, very dangerous place," Bassma Kodmani, spokeswoman for the Syrian National Council, the most representative Syrian opposition umbrella group, told reporters in Paris.

"I see no reason why opposition members would shoot at journalists," she said. "It is, therefore, most probably related to the regime."

French television reporter Gilles Jacquier was killed in Homs last month as a shell exploded amid a group of journalists covering protests in the city on a visit organised by the Syrian authorities.

Ms Colvin had been reporting from areas of conflict for two decades.

She had told The Times in 2004 that she spent about six weeks at a stretch in Baghdad at the height of the conflict there, and it was very stressful.

Her courage won her a number of awards. In East Timor, she was one of the only reporters who stayed in the UN refugee compound when all others had left. She also worked in Kosovo and Chechnya and was seriously wounded in Sri Lanka after she defied a government ban on reporting.

The Sunday Times itself said in an editorial in 2001: "Without reporters like Colvin, we would know much less of what is happening in the strife-torn regions and much less of the atrocities and persecution that still blight the planet."

Talking to The Times about war reporting, she insisted: "You just have to get out there and do it".