FAIZABAD, Afghanistan -- A motorcycle-riding suicide bomber attacked a line of people waiting outside a bank Saturday in eastern Afghanistan, killing at least 35 and wounding 125 in an assault the country's president blamed on the Islamic State group.
The accusation by President Ashraf Ghani, following local media reporting the Islamic State group's Afghan affiliate claiming the attack, would mark a major escalation in the extremists' nascent campaign of violence in the country.
While nowhere near as powerful as the Taliban, the affiliate's ability to strike at will would mark a new threat for the country to contend with as U.S. and NATO forces ended their combat mission at the start of the year. It also further stretches the Islamic State group's influence far beyond its self-declared caliphate stretching through a third of Iraq and Syria.
The attack in Jalalabad, the capital of eastern Nangarhar province, targeted a crowd of soldiers and civilians gathered outside the bank to receive their monthly salaries. The blast killed at least 35 people and wounded 125, said Ahmad Zia Abdulzai, a spokesman for the provincial governor.
Hours after the attack, Ghani blamed the Islamic State group for the bombing.
"In the horrific incident in Nangarhar, who took responsibility? The Taliban didn't claim responsibility. Daesh claimed responsibility for it," Ghani said, using an Arabic acronym for the group.
Local Afghan media quoted a previously unknown man who identified himself as a spokesman for the Islamic State group's affiliate in the country, claiming responsibility for the attack. It's not clear whether Ghani relied on this for his remarks or if he had other intelligence at his disposal.
The Taliban denied it carried out the bank attack and another elsewhere in the province that killed one civilian and wounded two.
"We condemn/deny involvement in both," Taliban spokesman Zabiullah Mujahid tweeted.
The Islamic State group, currently targeted by a U.S.-led coalition's airstrikes and an Iraqi ground offensive, has seen its public image rise dramatically since it seized much of Iraq last summer. Its online videos and propaganda, including scenes of its mass killings and beheadings, have caught the attention of many extremists.
In Libya, an Islamic State group affiliate has carried out attacks and beheaded 21 Coptic Christians from Egypt. Insurgents in Egypt's strategic Sinai Peninsula also have pledged to the group, while another purported affiliate in Yemen claimed a series of suicide bombings in March that killed at least 137 people.
Ghani previously has warned that the Islamic State group was starting to establish a presence in Afghanistan. He used his visit to the United States last month to reiterate his concerns.
"If we don't stand on the same line united, these people are going to destroy us," Ghani told a crowd of 600 people Saturday in Faizabad, the capital of northeastern Badakhshan province.
He called on the Taliban to join with the Kabul government, and said that any Taliban who switched allegiance to Islamic State group would earn the wrath of Afghanistan's religious leaders.
Ghani also blamed a recent attack on an army outpost, in which 18 soldiers were killed, eight of them beheaded, on "international terrorists." The Taliban aren't known to carry out beheadings.
The United Nations' Assistant Secretary-General for Human Rights, Ivan Simonovic, on a visit to Afghanistan, called the attack a "war crime."
"The use of suicide bombs and other devices in such an indiscriminate way by insurgent groups clearly constitutes a war crime, and those responsible for organizing or perpetrating such attacks must be brought to justice," he said in a statement.
Analysts and officials say the number of Islamic State supporters in the Afghan-Pakistan region remains small and that the group faces resistance from militants with strong tribal links. Taliban fighters and Islamic State supporters even have battled each other. However, the rise of even a small Islamic State affiliate could further destabilize the region and complicate U.S. and NATO efforts to end the 13-year Afghan war.
Taliban militants in Afghanistan and Pakistan owe their allegiance to Mullah Omar, a cleric who has led the Taliban since the 1990s but has not been seen or heard in public for years. Officials fear that an Islamic State push into the region could bring an infusion of guns and money, sparking brutal competition among local militants disenchanted with Mullah Omar's silence and eager to prove themselves with escalating atrocities.
In recent days, Ismail Khan, long a dominant figure in Afghanistan's western province of Herat, told The Associated Press that the numbers of Islamic State supporters are growing because of divisions in Ghani's government. Afghanistan's senior Shiite leader, Mohammad Mohaqiq, told the AP this month that Islamic State loyalists in southern Zabul province also were behind the abduction of 31 ethnic Hazara Shiites in late February.
