A rocket struck the presidential palace in Kabul and a second hit the Afghan capital's police headquarters on Tuesday, just two days before the presidential election, a police source said. No one was hurt.
The first rocket caused some damage inside the heavily fortified palace compound in the city centre. The second hit the main police headquarters nearby.
Taliban spokesman Zabihullah Mujahid, in a message sent to Reuters on a mobile phone, claimed the fighters had fired four rockets at the capital. He gave no further details.
Polls
Election campaigning officially ended at midnight after a final day that saw hectic rallies in support of Karzai and his main rival, former foreign minister Abdullah Abdullah.
Polls show Karzai likely to win Thursday's vote, but not with the outright majority required to avoid a second round. He is relying on the last-minute support of former guerrilla chieftains in a bid to tip the balance.
Recent polls give Karzai about 45 percent of the vote to 25 percent for Abdullah.
Since the polls were conducted, Karzai has secured the last-minute endorsements of some former fighter chieftains, hoping they help secure a first round victory.
General Abdul Rashid Dostum, an Uzbek fighter leader who won 10 percent of the vote in 2004, returned to the country from exile in Turkey and held a huge pro-Karzai rally in his northern home city of Shiberghen on Monday.
Karzai's two vice presidential running mates are also former fighter chiefs, from the Tajik and Hazara minorities. Last week he received the public endorsement of Ismail Khan, a former fighter leader in the western city of Herat.
More than 30,000 extra U.S. troops have this year arrived in Afghanistan that has been under US-West occupation for years, raising the total number of Western troops above 100,000 for the first time, including 62,000 Americans.
The NATO-led Western force said on Tuesday it would "refrain from conducting attacks on election day".
If Karzai fails to secure victory in a first round, he would most likely face Abdullah in a second round in early October.
PHOTO CAPTION
Afghan policemen keep watch after rockets hit Kabul August 18, 2009.
Reuters