BEIRUT, Lebanon — Syrian tanks reportedly entered the Homs neighborhood of Baba Amr on Thursday, raising fears of a ground assault in the most embattled district of the Syrian uprising., Reuters reported.

The siege of Homs, which is in its twentieth day, killed over 80 people yesterday, including two Western journalists who were hit by artillery fire when trying to escape from a makeshift media center that had been shelled. The situation is too dangerous for humanitarian forces to enter; the bodies of the journalists have yet to be recovered, and two other journalists in the attack are also stranded.

Rumors have swirled in recent weeks of a pending ground invasion in Homs. Marie Colvin, one of the journalists killed yesterday, wrote in The Sunday Times on February 19, "About 5,000 Syrian soldiers are believed to be on the outskirts of Baba Amr, and the FSA received reports yesterday that they were preparing a ground assault. The residents dread the outcome."

The Syrian government today denied any responsibility for the deaths of Colvin and Remi Ochlik, saying "We reject statements holding Syria responsible for the deaths of journalists who sneaked into its territory at their own risk," the Foreign Ministry said in a statement read out on state television, according to AFP.

Thursday saw no letup in the artillery barrage on the rebel districts of Homs, Reuters said. "Explosions are shaking the whole of Homs. God have mercy," Abdallah al-Hadi said from the city, according to the newswire.

The New York Times reports that the city is running dangerously low on food and other medical supplies; Colvin wrote Sunday that a baby born in a bomb shelter has been surviving on just sugar and water.