KABUL, Afghanistan -- A four-day blitz of bombings across Afghanistan has left the country reeling, raising fears that the Taliban -- which spent years fighting the Afghan state and its U.S. backers -- will be unable to maintain the peace.
Sunni extremists from the Afghan branch of the Islamic State, known as Islamic State-Khorasan or ISIS-K, have claimed at least one of the attacks, a bombing Thursday inside a crowded Shiite mosque in the northern city of Mazar-e Sharif that killed at least 31 people and injured more than 60.
On Friday, Taliban officials announced the arrest of a local Islamic State leader who they claimed was the "mastermind" of that attack. But just hours later, another bomb exploded at a Sunni mosque in northern Kunduz province, killing more than 30 people, and a mine was detonated near a market in Kabul.
The blasts capped a violent week, which included a double bombing outside a school in the ethnic Shiite Hazara district of Kabul and another attack in Kunduz on government workers.
All told, at least 77 Afghans have been killed and more than 160 wounded.
"These attackers are trying to build up a momentum of insecurity, to show that even with the Taliban in power, they cannot be stopped," said Faiz Zaland, an academic and political analyst in Kabul. Most of the attacks, he believes, were carried out by ISIS-K. "They are announcing a spring and summer of destruction."
So far, most of the bombings have struck Shiite communities, long a target of the Islamic State in Afghanistan.
ISIS views Shiites as apostates and over the past seven years it has carried out dozens of attacks on schools, mosques, hospitals and other facilities in Hazara neighborhoods. The Taliban also has a history of persecuting Shiites, especially during its first period in power during the late 1990s, but the new authorities have pledged to protect them.
On Friday morning, a group of Hazara protesters gathered in Kabul, demanding better security from the government.
"Above everything else, ISIS-K is an enemy of the Taliban," said Michael Kugelman, an expert on the region at the Wilson International Center for Scholars in Washington. "It wants to dent their credibility and legitimacy by showing that the Taliban can't protect the Afghan people from violence. It wants to shatter the Taliban's core message that they have restored peace to Afghanistan."
With no more NATO airstrikes to worry about and the Afghan economy in collapse, Kugelman said, the Islamic State has more advantages now in trying to destabilize the country. He also said the Taliban's use of "scorched-earth tactics" to crack down on ISIS can alienate local communities, making the government's job even harder.
Although both the Taliban and the Islamic State share a severe and ultraconservative vision of Sunni Islam, the latter group is both more radical in its ideology and more cruel in its methods. During the Afghan war, it competed with the Taliban for recruits and notoriety, carrying out attacks that included beheadings.
In a message posted to Twitter on Friday, the Taliban government's chief spokesman, Zabihullah Mujahid, condemned the recent bombings and called them "the work of circles that have nothing to do with Afghan society."
"The perpetrators of these crimes will soon be caught and punished for their evil deeds," he vowed.
Still, some Afghans and other observers question the government's sincerity, as well as its ability to protect the public.
They note that less than a month ago Taliban military officials held a ceremony honoring suicide bombers. Observers suggest that, in its desperation to win international support, the government might be slow to contain the threat from a more radical and violent rival.
"In this situation, the Taliban are presenting themselves as the good terrorists, fighting against the bad terrorists," said Davood Moradian, director of the Afghan Institute for Strategic Studies, which is now based in London. "In a way these attacks help them. Their strength does not lie in good governance, and they cannot deliver it. They are telling the world, 'We are the good terrorists, and if you want us to fight the bad ones, you need to recognize and support us.'"