Khost Gov. Tahr Khan Sabari was cut by glass from windows shattered in the blast but not seriously injured, Interior Ministry spokesman Zemeri Bashary told The Associated Press. Sabari's spokesman Arifullah Pashton said five other people, including two journalists who were meeting with the governor, also were slightly wounded.
Khost province, which borders Pakistan, is one of Afghanistan's most troubled. Seven CIA employees were killed Dec. 30 when a suicide bomber attacked an agency base there. On Wednesday, at least 15 people were wounded in a blast outside a shop in Khost city, the provincial center.
In Paktia province to the south, a suicide bomber on foot attacked a six-vehicle convoy of security workers, said provincial governor spokesman Roullah Samon. He said a supervisor of the security personnel was among those killed, but did not have details on the other victims.
Earlier Thursday, three rockets were fired into a residential area of Kabul, wounding three civilians. The Interior Ministry said in a statement that two of the rockets hit a house and the third landed in a garden. Local police said the attack was in the Qalafa neighborhood, about three miles (five kilometers) southeast of central Kabul.
There was no immediate claim of responsibility. But NATO's Afghan operation pointed the finger at the Taliban.
"The Taliban-led enemy has again demonstrated an absolute disregard for the Afghan people and their lives," said U.S. Lt. Gen. David Rodriguez, commander of NATO's International Security Assistance Force, in a statement.
In the eastern city of Jalalabad, about 5,000 demonstrators gathered to protest the Wednesday deaths of children in an explosion that they blamed on U.S. forces. Local officials said four children were killed, but NATO said Thursday that two died and that international troops were not responsible.
The blast about 15 miles (25 kilometers) south of Jalalabad, tore through a group of soldiers and civilians while the soldiers were visiting a road-construction project. Some 80 civilians and three soldiers were wounded.
Afghan police said the blast was caused by a passing police vehicle hitting a mine, but the protesters blamed it on the U.S. soldiers. They shouted "Death to America" and burned an effigy of President Barack Obama.
"While we continue to believe these casualties were not caused by ISAF operations, we will continue to assist our Afghan friends and partners," the forces' deputy chief of staff for operations, U.S. Maj. Gen. Michael Regner, said in a statement.
Also Thursday, two U.S. senators visiting Afghanistan said American drone strikes just over the border in Pakistan were key to defeating terrorists in the region.
Attacks by the unmanned aircraft are a controversial element of U.S. strategy. Pakistan has publicly condemned them as a violation of its sovereignty, and civilian deaths in the strikes stoke anger against the U.S.
But senators John McCain and Joseph Lieberman told journalists in Kabul that they support the strategy.
McCain said the strikes "have knocked al-Qaida and other Islamic extremist organizations off-balance" and that the U.S. is working with Afghanistan and Pakistan to reduce civilian suffering caused by them.
"This is a war, and it is a war in which the enemy is being brutal, and the only way to stop them is with force," Lieberman said. "And in the particular case of the drones they are a critical element of our effort, our campaign, our strategy to deny the terrorists who are terrorizing the people Afghanistan and of Pakistan a safe haven from which to strike."
Since the CIA attack in Khost province, suspected U.S. drones have carried out five strikes in Pakistan's neighboring North Waziristan region. The area is believed to be a hide-out for militants involved in the attack.
The latest strikes, on Wednesday, killed 13 people.
