JEFFREY BROWN: And now to Syria, where the government intensified its assault against the city of Homs, raining down rockets and bombs on the opposition stronghold.
In all, across the country, activists said more than 70 people had been killed today. Among them were two Western journalists, an American reporter working for the British Sunday Times and a French photojournalist.
Tim Ewart of Independent Television News narrates this report.
TIM EWART: The bombardment of Homs has again been relentless.
Syrian rebels said a short while ago that 35 people are known to have died today in the beleaguered suburb of Baba Amr. Many more bodies lie under the rubble. Activist Haled Abu Saba says that, in this building, "Your blood has mixed with Syrian blood."
It is the makeshift media where the two Western journalists were killed, targets, the rebels claim, of a deliberate rocket attack. Marie Colvin of The Sunday Times sacrificed her life to a career at which she excelled. A veteran of numerous war zones, she'd lost an eye to a grenade blast in Sri Lanka. Remi Ochlik, who died with her, was a French photojournalist.
Paul Conroy, a Sunday Times photographer, was among six people injured. And Rami al-Sayed, the Syrian cameraman who recorded so much of the violence, was killed by shrapnel earlier.
On "News at 10" last night, Marie Colvin talked of the horrors unfolding in Baba Amr.
MARIE COLVIN, The Sunday Times; I think the sickening thing is the complete merciless nature. They're hitting civilian buildings absolutely mercilessly and without caring. And the scale of it is just shocking.
CHRISTINA LAMB, The Sunday Times: I don't remember Marie ever saying that somewhere was too dangerous for her to go to. I think the line for her was a lot further than it was for others of us.
TIM EWART: In Baba Amr, where they have mourned too many dead, there was this evening a desperate plea for help.
YOSIF HOURIAH, Syrian activist: People known that we are suffering, but no one helps us. We need real help.
TIM EWART: Tragically, Marie Colvin, a reporter brave enough to help convey that message to the world, was killed as she worked amid the ruins.
JUDY WOODRUFF: And now to a graphic account of the battle for Homs, now in its 19th day.
A French photojournalist known as Manny has lived and filmed inside the besieged city for the past month. His footage offers a rare glimpse of the conflict consuming Syria.
Using Manny's images, Jonathan Miller of Independent Television News tells the story of what's happening there.
A warning: Some of the pictures and the stories are distressing.
JONATHAN MILLER: They call Homs the capital of the revolution. The revolt against President Bashar al-Assad has been going on for nearly a year, but on Friday, Feb. 3, his forces unleashed a ferocious bombardment of residential neighborhoods in Homs, a little girl and her brother both badly wounded.
GIRL (through translator): After we crossed the road, the shell hit us. I fell down on the ground, but my cousin was still awake. After that, I don't know what happened.
JONATHAN MILLER: No one could bear to tell her that her father and youngest brother are dead.
We're in Bayada district. It's 10:00 in the morning. And fighters from the Free Syrian Army are engaged in a gun battle that started at 3:30 a.m. As they wait, the muezzin is broadcasting a eulogy for a dead fighter, a martyr, a tense, but momentary lull. Then it starts all over again.
JONATHAN MILLER: They're attacking the government security building across the road, headquarters of the hated Mukhabarat secret police.
JONATHAN MILLER: Manny, the filmmaker, finds himself at the heart of the firefight.
JONATHAN MILLER: Urban guerrilla warfare like this is relentless and terrifying. The fighters appear fearless and take crazy risks.
JONATHAN MILLER: Khalidiya district, right next to Bayada, two days earlier. Residents pour onto the streets to mourn 138 people killed overnight by government shelling.
There aren't enough coffins for all those who've been killed, so men are simply wrapped in white shrouds. The atmosphere is highly charged.
An imam leads prayers for the dead.
MAN (through translator): We pray for our martyred dead. Shelling people is what cowards and scoundrels do.
JONATHAN MILLER: Back at Mukhabarat headquarters, the battle is raging. Free Syrian forces have detonated a bomb below the rooftop position where government snipers are trapped.
After more than 12 hours, the snipers are still putting up a fight. Casualties are mounting, a minibus ambulance and then a breakneck race to a makeshift field hospital.
There's little dignity in all this.
Friday is protest day. It's almost a carnival atmosphere, but it's a carnival of defiance, as the people of Homs tell their president what they think of him. Mothers, children, fathers and fighters, this mass of humanity dances for its hurriya, its freedom, an unstoppable energy battling a seemingly immovable force.
Free Syrian fighters have entered the government security building, room-to-room fighting now, stairwell to stairwell. It's a humiliation for President Assad.
JONATHAN MILLER: With bullets still flying, fighters make off with boxes of much-needed ammo.
The morning after, the Mukhabarat secret police building has been gutted, as has the local post office. Down the street is a long queue for bread. With parts of the city besieged, you can no longer get to shops in neighboring districts.
MAN (through translator): The citizens are hungry for bread. This is the only bakery in the area, because the snipers are taking out more people than they need. This is why it's crowded.
JONATHAN MILLER: A couple of blocks away, and you're in Sabil district, where many belong to the president's Alawite sect. They have not been attacked -- Homs now a patchwork, dividing along sectarian lines.
JEFFREY BROWN: A United Nations spokesman said today its top humanitarian official will go to Syria to assess the situation and call for urgent access to emergency aid for those in need.
According to the U.N., more than 5,400 people have now been killed in the uprising that began 11 months ago.