Afghan authorities say at least 13 people have been killed in a bombing in southern Afghanistan.
The attack took place Wednesday in the Nahr-e-Sarraj district near Lashkar Gah, the capital of Helmand province. NATO said its helicopters evacuated at least 40 of the wounded to hospitals.
Afghan officials say the bomb exploded as people gathered to receive free seeds as part of a program aimed at discouraging farmers from growing opium poppy.
A provincial government spokesman said earlier the explosion was caused by a suicide bomber, but the Interior Ministry said the bomb was attached to a bicycle.
U.S.-led NATO troops and Afghan forces have been clearing Taliban insurgents in Helmand's Marjah region since February and are getting ready to begin an offensive in neighboring Kandahar in the coming months.
On Wednesday, the chairman of the U.S. Joint Chiefs of Staff, Admiral Mike Mullen, told reporters in Kabul that taking control of Kandahar is key to reversing the momentum of the Taliban.
Pentagon spokesman Geoff Morrell said Tuesday that preliminary efforts to take control of the southern Afghan city are underway.
Morrell says U.S. special operations forces are securing roads in and out of the city and working with tribal leaders. Morrell declined to say when the offensive will begin, but U.S. officials in Afghanistan say the campaign is expected to begin in June.
Separately, Afghan President Hamid Karzai met with representatives of the militant group Hizb-i-Islami on Tuesday. A member of the Hizb-i-Islami delegation said the two sides wrapped up a round of peace talks with no breakthrough but a commitment to continue dialogue.
The group has presented Mr. Karzai with a 15-point peace plan that includes a demand that foreign troops begin withdrawing from Afghanistan in July.
Some information for this report was provided by AP, AFP and Reuters.