Demonstrators hurled grenades at a U.S. base in northern Afghanistan, and a gun battle left two Afghans dead and seven NATO troops injured Sunday in the escalating crisis over the burning of Muslim holy books at an American airfield.
More than 30 people have been killed, including four U.S. troops, in six days of unrest. Still, the top U.S. diplomat in Afghanistan said the violence would not change Washington's course.
"Tensions are running very high here, and I think we need to let things calm down, return to a more normal atmosphere, and then get on with business," Ambassador Ryan Crocker told CNN's "State of the Union."
"This is not the time to decide that we're done here," he said. "We have got to redouble our efforts. We've got to create a situation in which al-Qaida is not coming back."
In other violence, a suicide car bomber struck early today at the gates of Jalalabad airport in eastern Afghanistan, killing nine people in a large blast, officials said.
The Taliban said the attack on the airport, which serves both civilian and international military aircraft, was revenge for the burning of Muslim holy books.
Among the dead were six civilians, two airport guards and one soldier, Nangarhar provincial police spokesman Hazrad Mohammad said. Another six people were wounded, he said.
NATO forces spokesman Capt. Justin Brockhoff said that no international forces were killed in the early morning attack and that the installation was not breached by the blast.
Sunday's attack on the military base came a day after two U.S. military advisers -- a lieutenant colonel and a major -- were found dead after being shot in the head in their office at the Interior Ministry in the heart of the capital. The building is one of the city's most heavily guarded buildings, and the slayings raised doubts about safety as coalition troops continue their withdrawal.
The incident prompted NATO, Britain and France to recall hundreds of international advisers from all Afghan ministries in the capital. The advisers are key to helping improve governance and preparing the country's security forces to take on more responsibility.
A manhunt was under way for the main suspect in the shooting -- an Afghan man who worked as a driver for an office on the same floor as the advisers who were killed, Interior Ministry spokesman Sediq Sediqi said. He did not provide further details about the suspect or his possible motive.
The Taliban claimed that the shooter was one of their sympathizers and that an accomplice had helped him get into the compound to kill the Americans in retaliation for the Quran burnings.
Afghanistan's defense and interior ministers were to visit Washington this week, but they called off the trip to consult with other Afghan officials and religious leaders on how to stop the violence, Pentagon press secretary George Little said.
The protesters in Kunduz province in the north threw hand grenades to express their anger at the way some Qurans and other Islamic texts were disposed of in a burn pit last week at Bagram Air Field, north of Kabul.
President Obama and other U.S. officials have apologized for the burnings, which they said were a mistake. But their apologies have not quelled the anger of Afghans, who say the incident illustrates foreigners' disrespect for their culture and religion.
Last week, during a protest in Nangarhar province in the east, two other U.S. troops were killed when an Afghan soldier turned his gun on them.
In Sunday's protest in Kunduz, thousands tried to enter the district's largest city. Armed individuals in the crowd fired on police and threw grenades at the U.S. base on the city outskirts, said Amanuddin Quriashi, administrator in Imam Sahib.
Seven NATO troops were wounded by the grenade. One protester was killed by troops firing from the U.S. base, and another was killed by Afghan police, Quriashi said.
A NATO spokesman said that an explosion occurred outside the base but that the grenades did not breach its defenses.