KANDAHAR, Afghanistan — A man identified on tape as the Taliban's new top field commander warned Wednesday that new recruits were volunteering as suicide bombers and that fighters would continue their holy war until western powers leave Afghanistan.

Violence struck throughout the country with two bomb blasts that killed four people, including a Finnish soldier in the usually quiet north. NATO said it attacked a meeting of Taliban leaders in the south, killing an unspecified number of militants.

Shuhabuddin Athul, a Taliban spokesman, played an audio tape over the telephone to an Associated Press reporter that Athul said was a recording of Dadullah Mansoor, brother and replacement of Mullah Dadullah, the top Taliban commander shot to death in a U.S. operation this month in southern Afghanistan.

The man on the tape said Taliban fighters were ready to avenge his brother's death and would "pursue holy war until the occupying countries leave.''

"They will pursue their attacks against occupying countries and the (Afghan) government,'' he said in a first public statement. "The number of suicide attackers is increasing. ... All of the Taliban, we are ready to carry out suicide attacks, roadside bombs and ambushes against the Americans and the government.''

There was no way to verify that the voice was really Mansoor's.

Mullah Dadullah, a one-legged veteran who orchestrated an intensifying campaign of suicide attacks and beheadings, had long been a top lieutenant of Taliban leader Mullah Omar. Al-Qaida's No. 2 leader, Ayman al-Zawahri, hailed Mullah Dadullah in a videotape released Tuesday.

Athul has said that Mansoor was one of five prisoners released in March in exchange for kidnapped Italian journalist Daniele Mastrogiacomo. He was named as Mullah Dadullah's replacement last week, Athul said.

In a sign that the insurgency could be spreading, a bomb blast killed a Finnish soldier and an Afghan civilian in the northern town of Maymana, about 100 metres outside a Norwegian-led base. Four Norwegian soldiers were slightly wounded.

The soldiers had been on their way to a hospital for the opening of a reconstruction project, said Lt.-Col. John Inge Oeglaend, a Norwegian military spokesman.

Northern Afghanistan is relatively calm, compared with the south and east, but it has seen a run of attacks in recent weeks. A suicide bomber Saturday killed 10 people in the northern city of Kunduz, including three German soldiers who were walking through a market.

"No parts of Afghanistan are safe, but the north has normally been quieter,'' Oeglaend said. "But this is one of the threats we have been prepared for and have been aware of for a long time.''

In the capital, Kabul, a suicide attacker on a motorbike blew himself up next to highway police guarding a road construction project, killing one policeman and a civilian, officials said.

An SUV carrying foreigners that had its window shattered in the attack may have been the intended target, said Gen. Ali Shah Paktiawal, the Kabul police director of criminal investigations. The SUV drove off and officials didn't know what group or country it was from.

NATO's International Security Assistance Force said "precision weapons'' targeted a meeting of Taliban leaders Tuesday in the southern province of Helmand. A military statement said "all of those who died were enemy insurgents,'' but did not indicate how many were killed, and Afghan officials said they were not aware of the attack.

In western Afghanistan, suspected Taliban militants beheaded a man and left his body in the Shindand bazaar in Herat province, said Mohammad Naieem, a border police official.

The man's head was placed on his chest along with a letter purportedly from the Taliban warning that anyone working with foreign military forces would be killed, Naieem said. The man was apparently taken Tuesday night and his body was discovered Wednesday.

In Khost province, a roadside bomb exploded Tuesday as two trucks full of Afghan soldiers were driving by, killing four soldiers and destroying a truck, said Wazir Padshah, a provincial police spokesman.

Attacks in Afghanistan have increased in recent weeks. More than 1,800 people have been killed in insurgency-related violence this year, according to an AP count based on U.S., NATO and Afghan officials.