GWEN IFILL: The conflict in Syria threatened to spread today, as plans for a cease-fire appeared close to collapsing. Syria fired at refugees across the Turkish border, and, in Lebanon, a television cameraman was reportedly shot and killed by Syrian soldiers.
We have a report from Alex Thomson of Independent Television News.
A warning: This story contains some disturbing images.
ALEX THOMSON: Today, the Syrian civil war spilled across an international frontier.
MAN (through translator): They fired from two sides and wounded more than four people who we took to the hospital. But three people who were wounded died in the camp because we could not evacuate them.
ALEX THOMSON: They shout "God is great" as shots ring out at the Turkish-Syrian border. Nobody knows why Syrian appear to have fired into a Turkish refugee camp today, but at least one person was killed, several more injured.
And still they come across, a Syrian activist website showing exhausted people guided to a safe country by Turkish troops. All signs that the coming cease-fire will be honored seem to be fading fast. Tomorrow morning, Syrian troops and heavy weapons have to leave towns and cities. Thursday morning, the cease-fire begins, all set up by the former U.N. boss Kofi Annan when he met the Syrian leader recently.
But Syria now suddenly wants written guarantees that the rebels will stop fighting. Senior European diplomats today called that completely unacceptable. But Syria says there's a war to fight.
GEORGE JABARI, Syrian parliament member (through translator): If government forces withdraw from some area, the armed crews will permeate through these regions, which will be a threat to public safety.
ALEX THOMSON: Kofi Annan due in Turkey tomorrow and then on to Iran. Today, the Syrian foreign minister is due in Russia, Moscow of course ever supportive of Damascus.
This was Homs today, the epicenter of the uprising. Rebels and observers say the bombardment here from tanks and artillery the heaviest since the war began. Rebel groups and human rights observers estimate around 100 people are being killed every day across Syria, 1,000, they say, in the past week, and what seems to be evidence here again of something more discriminating than shelling of civilian areas, the bodies of people lined up against a wall and shot dead at close range.
They said this was another mass execution of people by Syrian government forces. That looks plausible, but is, as yet, impossible to verify. It just could be that Syria is serious about cease-fire and this is some kind of final push, but few believe that.
And the prospects for a lasting cease-fire, in fact, any cease-fire, do not look good tonight, Turkey's saying she's actively considering all options, up to and including sending her troops into Syria to set up more effective corridors for civilians who need to get out.