Al Jazeera's Hashem Ahelbarra, reporting from the capital, Kabul, said the fighting lasted for at least two hours.
"Five Taliban suicide bombers seized a building near police headquarters in the city of Gardez with the aim of storming that headquarters to inflict heavy casualties on the policemen. They were intercepted," he said.
"A spokesperson of the governor of Paktia told Al Jazeera that two Taliban suicide bombers were killed and that 12 [people] were injured - four policemen and the rest civilians, and that an Isaf (Nato-led International Security Assistance Force) soldier was also injured.
"A spokesperson of the Taliban told Al Jazeera that the aim of this operation was to tell the international community to 'stop thinking about parliament and the Afghan government, because you have to bear in mind that we are the ones to call the shots in Afghanistan'."
Eastern Afghanistan has seen some of the worst violence by the Taliban, which is targeting the Western-backed government of Hamid Karzai, the Afghan president, and 113,000 US and Nato troops in the country.
Barack Obama, the US president, and Nato allies have pledged to deploy an extra 37,000 troops to Afghanistan, which will take the total number of foreign troops in the country to 150,000.