Veteran journalist Marie Colvin
The authorities in Damascus have claimed they did not know that journalists Marie Colvin and Rémi Ochlik were in Syria.
"The authorities had no information that the two journalists had entered Syrian
territory," information minister Adnan Mahmoud told AFP news agency.
Reuters earlier confirmed that the journalists killed in Syria on Wednesday were Colvin, of the Sunday Times and French photographer Ochlik.
The Western journalists were killed as Syrian regime forces shelled the flashpoint city of Homs, an activist has said.
Several other people were also killed and wounded, activists added.
The two were killed when a shell crashed into a makeshift media centre set up by anti-regime activists in Baba Amr district, under siege since February 4, activist Omar Shaker told AFP from the area.
He said three other foreign journalists were wounded.
Both Colvin and Ochlik were veteran correspondents of wars in the Middle East and elsewhere.
Colvin was a fearless reporter who lost an eye when she suffered a shrapnel wound while working in Sri Lanka in 2001. In public appearances after that attack, she wore a black eye patch.
The Syrian conflict is particularly dangerous for journalists to cover as opposition and rebel forces are mostly holed up in enclaves.
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.
Last week New York Times reporter Anthony Shadid died of an asthma attack while trying to reach an opposition zone.
Over 100 people were reportedly killed across the country on Tuesday, including more than 40 in Homs as troops attacked opposition strongholds. Others have said the death toll in Idlib is higher.