A wave of attacks by Taliban insurgents in eastern Afghanistan Monday left at least 27 people dead, raising security concerns before the nation's presidential election.
Zabul province was the scene of two major attacks. Local authorities say a roadside bomb tore through a tractor that was transporting a group of civilians, killing at least 12 people.
Also in Zabul, officials say Taliban fighters attacked a convoy near the provincial capital, Qalat, and killed six security guards.
Earlier Monday, a suicide bomber attacked the mayor of Mehterlam, the capital of Laghman province, killing the mayor, three of his bodyguards and three civilians.
In Kabul, President Hamid Karzai officially registered as a candidate for re-election in the August 20 presidential election.
Mr. Karzai, who has two running mates - current Vice President Karim Khalili and former Vice President Mohammad Qasim Fahim - promised to bring peace and security to the country.
He said he has decided to run again to serve the welfare and interests of the people of Afghanistan.
Other candidates have until Thursday to register. However, the opposition is struggling to name a candidate with broad enough support to challenge Mr. Karzai.
He has led Afghanistan since the U.S.-backed invasion ousted the Taliban in 2001. He won an election in 2004.
A worsening Taliban insurgency and charges of government corruption have weakened Mr. Karzai's image at home and abroad. However, no strong challenge to his re-election bid has emerged.
Some information for this report was provided by AFP and AP.