The attacks have resulted in the death of hundreds of people, mostly militants.
The deaths include 16 U.S. soldiers killed when their Chinook helicopter was shot down on 28 June. That was one of the heaviest U.S. casualties since the 2001 ouster of the Taliban.
The deaths also have included 21 people killed in a suicide bomb attack in Kandahar, also in June. It happened at the funeral of a senior cleric assassinated days earlier.
And in recent months, three senior pro-government clerics have been assassinated in southern Afghanistan. The last incident happened on 8 July in Paktika when unknown assailants stabbed to death the head of the Paktika Ulema Council Agha Jan and his wife. Paktika Governor Gulabuddin Mangal has accused the Taliban of having committed the killing.
Afghan Defense Minister Abdul Rahim Wardak said yesterday that foreign fighters from Arab and neighboring countries are carrying out the attacks with the Taliban.
Wardak told reporters that the scope of the violence of the recent months comes as a surprise.
"Following the melting of the snow, there has been a significant increase in terrorist attacks, more than we expected," Wardak said.
His comments came as authorities in southern Afghanistan confirmed the death of 10 Afghan police officers. Six of them were beheaded and their bodies and heads were dumped near the border with Pakistan. Beheading has been rare in the conflict in Afghanistan.
Afghan Interior Minister Ali Ahmad Jalali said yesterday that the police officers had been abducted on 8 July following an ambush in southern Afghanistan's Helmand Province.
"In Helmand, in the Deshu district, a patrolling group of Afghan border forces came under attack by a large number of terrorists while it was traveling from Barancha region to Rubatak," Jalali said. "As a result of the fighting, unfortunately, they took with them 10 members of the border force, they martyred four of them in one place, the other six men were killed just 200 kilometers away from the Pakistani border. Then the kidnappers escaped to the Gerdi Jangal border."
Jalali condemned the killings as un-Islamic and inhuman.
"Those people who commit such crimes are not Muslims and they are not human beings because this is against Islam and humanity," Jalali said.
Afghan officials have said that the Taliban and their allies are stepping up their attacks in an effort to disrupt upcoming parliamentary and local elections. The elections -- scheduled for 18 September -- are considered another key step in the Afghanistan's path toward peace and stability.
Afghan election officials say three Afghans working in support of the elections have been killed in recent months.
Vahid Mozhdeh, an Afghan writer and security expert based in Kabul, believes that the attacks are aimed at creating fear among government forces in order to force them to quit. He adds that the militants also trying to create difficulties for the U.S. forces based in Afghanistan.
"One reason that can explain the stepping up of [attacks] is the wish of Al-Qaeda for the Americans to be blighted in Afghanistan as they are in Iraq and to suffer more casualties," Mozhdeh said.
Mozhdeh told RFE/RL that Taliban forces and their allies are becoming more organized. He said they are changing their tactics and using more effective explosives.
"Fewer fighters are involved, they come and attack using motorbikes and quickly escape," Mozhdeh said. "The Taliban want to put people and the coalition forces against each other. They conduct operations somewhere and then leave and then coalition forces carry an attack against them there but mostly civilians get hurt. We've been witnessing a series of suicide attacks which in the past had not been common in Afghanistan. Therefore, we see that the experience of violence is spreading from Iraq to Afghanistan."
The Afghan defense minister said earlier this month that he received intelligence that Al-Qaeda is regrouping and intends to bring Iraq-style bloodshed to Afghanistan.
He also warned that his country could face several months of intense violence ahead of the elections.