HARI SREENIVASAN: Debt troubles in Europe shook up Wall Street and other world markets today. The Dow Jones industrial average lost 131 points to close at 12,381. The Nasdaq fell 44 points to close at 2,759. Oil prices also continued their retreat, dropping more than 2 percent to settle at nearly $98 a barrel in New York trading.
Five NATO soldiers were killed today in Afghanistan, four in a roadside bombing in the east and one in an explosion in the south. Alliance officials gave no details on the nationalities, but the majority of forces in the east are American.
Meanwhile, the Taliban denied reports that its leader, Mullah Omar, had been killed in Pakistan. An Afghan TV news channel reported Omar was shot dead while being moved from Quetta to North Waziristan. Afghan officials said they are not sure what happened to the Taliban leader.
LATIFULLAH MASHAL, Afghan Intelligence Agency: So far, we cannot confirm the death or killing of Mullah Omar officially. But we can confirm that he has been disappeared from his hideout in Quetta, Balochistan. We hope he's dead, but we cannot confirm it yet.
HARI SREENIVASAN: The Afghan TV report said Omar had been helped by Gen. Hamid Gul, the former chief of Pakistani intelligence. Gul denied that.
The Pakistani Taliban claimed today it was responsible for an 18-hour attack on a military base in Karachi that killed 10 people. The group said it was revenge for the killing of Osama bin Laden.
We have a report narrated by John Sparks of Independent Television News.
JOHN SPARKS: Burnt-out and worthless, several military aircraft left to smolder on the tarmac, this the headquarters of Pakistan's naval air unit. It was protected by troops and rung with barbed wire, but no match it seems for a small group of militants bent on martyrdom.
They were dressed in black, like characters from a "Star Wars" film, said one official, and they were heavily armed with machine guns, rocket launchers, and grenades. Six members of the Pakistani Taliban blew up two aircraft, a helicopter and a jet fuel tanker.
The Mehran naval base is located in Karachi, Pakistan's biggest city and commercial hub. The attacks began at 11:00 p.m., and were reportedly launched simultaneously, on the main entrance, at the museum gate at the rear, and from the Shah Faisal neighborhood on the east side.
REHMAN MALIK, Pakistani interior minister: The -- the terrorists have taken over a building within this complex. And we are going to launch an operation.
JOHN SPARKS: This another embarrassment for the military, after it failed to detect or stop the U.S. raid against Osama bin Laden three weeks ago.
The Pakistani media provided blanket coverage as the battle on the base lasted 17 hours. Ten soldiers were killed in the fighting. By late afternoon, the base was back in the military's hands, but few celebrated the fact; two militants had got away.
HARI SREENIVASAN: Pakistani authorities said four attackers were killed, in addition to the two who escaped.
The president of Syria, Bashar al-Assad, is now facing additional sanctions from the European Union. The E.U. announced today it is freezing assets and imposing a visa ban on Assad and nine other Syrian government figures. It cited the Syrian crackdown on protesters. Human rights activists say more than 900 people have been killed by security forces since the uprising began two months ago.
Republican Tim Pawlenty has formally announced he is running for his party's nomination for president in 2012. The former governor of Minnesota released an Internet video laying out plans for his campaign last night.
And, today, he spoke in Des Moines, Iowa, site of next year's leadoff presidential caucuses.
TIM PAWLENTY, (R) presidential candidate: If we want a new and better direction, we're going to need a new and better president. President Obama's policies have failed. But, more than that, he won't even tell us the truth about what it's really going to take to get out of this mess that we're in.
HARI SREENIVASAN: Pawlenty's official entry into the race came hours after fellow Republican Mitch Daniels decided not to run. The two-term governor of Indiana took his name out of consideration on Sunday. He cited the wishes of his wife and daughters.
An erupting volcano in Iceland threatened air traffic in the United Kingdom and Ireland today. The Grimsvotn volcano began spewing dense ash on Saturday. It reached 33,000 feet, the altitude where passenger jets fly. British Airways and KLM were among airlines that canceled Tuesday morning flights to and from Scotland, ahead of the ash cloud's arrival there.
Another Icelandic volcano erupted last year, grounding thousands of flights and stranding millions of travelers across Northern Europe.
Those are some of the day's major stories.