JIM LEHRER: Next: the protests in Egypt.
Security officials said a demonstrator and a policeman were killed today. That brings the total to six dead in two days of clashes.
We start with a report from Cairo by Jonathan Rugman of Independent Television News.
JONATHAN RUGMAN: In the heart of Cairo's concrete jungle, police fired tear gas and rubber bullets to break up what is now the biggest challenge to Hosni Mubarak's 30-year rule.
In Cairo, the protesters may have numbered a few thousand at most. But, amid the tear gas, the stones, the skirmishes, the picture emerging here is extraordinary, because the defiance is unprecedented.
Protests were officially banned today. Hundreds across Egypt have been arrested, with plainclothes police seen frog-marching suspects away.
We followed protesters fleeing the tear gas into a warren of backstreets.
"This is not over," one of them told us. "It's only just begun."
MAN: It's police cars, they are just shooting the people. They are shooting the people. No mercy. They have no mercy.
JONATHAN RUGMAN: Rubber bullets?
MAN: Rubber bullets. They have no mercy. They attack people directly. They do not get them attention, nothing, nothing.
JONATHAN RUGMAN: Will you carry on protesting?
MAN: Yes. I will protest until they leave.
JONATHAN RUGMAN: The protests began outside Cairo's clubs for journalists and lawyers. They called for fresh elections after those last November gave the president's party a widely ridiculed 93 percent. Some journalists trying to film here were attacked by plainclothes police.
This was Cairo's Freedom Square in the early hours of this morning, failing to live up to its name. Protesters had vowed to stay up overnight, but the police were having none of it. Among the injured and tear-gassed were Egypt's educated, Internet-savvy future, inspired by Tunisia's revolt and in search of a country no longer led by Hosni Mubarak.
MAN (through translator): As if we are not humans, they are beating us like dogs. God will punish them.
JONATHAN RUGMAN: He's now 82 and still staring down from billboards outside Cairo's vast army barracks. Rumors that he wants his son to replace him are only adding to the sense of despair here.
Tonight, security forces tried to ward off small bands of protesters calling for Egypt's president to abandon power. This is uncharted territory for an aging leader. And his opponents are showing no sign of giving up yet.
JIM LEHRER: At the White House today, spokesman Robert Gibbs said Egypt is a strong ally, but he declined an opportunity to express support specifically for Mubarak.
And, at the State Department, Secretary Hillary Clinton urged calm.
U.S. SECRETARY OF STATE HILLARY RODHAM CLINTON: As we monitor this situation carefully, we call on all parties to exercise restraint and refrain from violence. We support the universal rights of the Egyptian people, including the rights to freedom of expression, association,and assembly.
And we urge the Egyptian authorities not to prevent peaceful protests or block communications, including on social-media sites.