A roadside bomb in the eastern city of Jalalabad killed two policemen on Monday and wounded another 25 people. A second blast caused no injuries.
Interior Ministry spokesman Zemeri Bashary said the bomb was planted on a central road and exploded as a police convoy drove past. Of the injured, 16 were police officers and the rest were passers-by.
Another bomb that detonated later in another part of the city caused no damage or injuries and the target was unclear. Jalalabad is on a key trade route from Pakistan and has been the site of numerous insurgent attacks in recent weeks.
The Taliban claimed responsibility for the bombings, which spokesman Zabiullah Mujahid said were aimed at the police.
On Feb. 19, five suicide bombers dressed in security force uniforms stormed a Jalalabad bank and killed 38 people.
Earlier in Jalalabad, more than 500 people staged an anti-American demonstration demanding the release of Afghans being held at Guantanamo Bay and at a facility on a U.S. military base at Bagram airfield, just outside Kabul. The were also protesting military operations by U.S.-led coalition forces that have resulted in civilian casualties.
The protest came one day after President Hamid Karzai rejected as insufficient a U.S. apology for the mistaken killing of nine Afghan boys in a NATO air attack last week, and told the coalition that civilian casualties were no longer acceptable. The boys were collecting firewood in the remote Pech Valley in eastern Kunar province and were mistaken for insurgents.
Civilian deaths have jumped primarily because of increased attacks from insurgents, according to U.N. data. But allegations of civilian deaths from NATO forces often cause much more anger, and are a major source of strain in the already difficult relationship between Karzai's government and the United States.