By Hamid Shalizi and James Mackenzie
KABUL (Reuters) - Islamic State is threatening more attacks against Afghanistan's Hazara minority after Saturday's suicide blasts in Kabul that killed 80 people, pledging to retaliate against support by some in the mainly Shi'ite group for the Assad regime in Syria.
But assessing the threat from Daesh, as Islamic State is known in Afghanistan, is difficult. Some officials question whether an ultra-radical Sunni movement largely confined to an area near the border with Pakistan can sustain more attacks.
Omar Khorasani, a Daesh commander, said Saturday's bombing at a rally by thousands of Hazara protesting about the route of a new power line was in retaliation for the support offered by some Hazara to the regime in Syria.
Many Hazara have gone through Shi'ite-governed Iran to fight for the government of President Bashar al-Assad, a fellow Shi'ite, against Islamic State.
"Unless they stop going to Syria and stop being slaves of Iran, we will definitely continue such attacks," he told Reuters via telephone from an undisclosed location. "We can and we will strike them again," he added.
The government says it has been hitting Daesh hard even before Saturday's blasts in Kabul, one of the most deadly in the country since the start of the Taliban insurgency in 2001.
It said government forces had killed hundreds of insurgents in the past two months in assaults on Daesh strongholds in the eastern province of Nangarhar, which straddles the highway from Kabul to the Pakistani city of Peshawar.
In the latest fighting, at least 122 insurgents were killed in the past 24 hours, it said on Tuesday. However, the numbers could not be independently confirmed.
Nevertheless, Saturday's attack by Islamic State on the Shi'ite minority adds a dangerous complication to the war the Western-backed government in Kabul has been fighting with Taliban insurgents.
As well as the risk of dragging Afghanistan into Islamic State's wider campaign in the Middle East, it raised the specter of sectarian violence, something Afghanistan, a majority Sunni country, has largely been spared during decades of war.
But while seeing the threat, officials are cautious about whether the attack represents a real turning point for Daesh, which has been under heavy pressure this year from both U.S. air strikes and an Afghan ground offensive.
"Having a couple of people that you've hired put on a suicide vest and sneak into a crowd of many thousands really is not that sophisticated," said U.S. military spokesman Brig. Gen. Charles Cleveland.
ATTACKED IN PAKISTAN AS WELL
On the ground, the NATO-led coalition advising government forces estimates the number of Daesh fighters at between 1,000-3,000, many of them former members of militant groups like the Taliban Movement of Pakistan (TTP), the Islamic Movement of Uzbekistan or the Afghan Taliban itself.
On the Pakistani side of the border, many Daesh fighters operating in Afghanistan are from the Orakzai tribe that have also been hit hard by the Pakistani military, according to an Afghan security report seen by Reuters.
According to Afghanistan's interior ministry, 654 Daesh and Taliban fighters, including several senior commanders, have been killed in Nangarhar province in the last two months.
But while the movement may have been limited to Nangarhar, that need not stop it from seeking to spread terror and raise its profile with more attacks on civilian targets, officials said.
"That's our concern, these high profile attacks, they are effective because they're not that difficult to achieve," Cleveland told reporters in Kabul.
The Hazara, a minority that has long suffered violence and discrimination in Afghanistan, have responded with fury to the attack, accusing the government of inaction or worse. With President Ashraf Ghani's unwieldy national unity government riven by infighting, their anger adds an unpredictable new threat of political instability.
Government and coalition officials insist however that Islamic State is being hit hard.
The Afghan army has launched its first major offensive since the holy month of Ramadan in Nangarhar.
According to an interior ministry report, 654 Daesh and Taliban fighters, including several senior commanders have been killed in Nangarhar in the last two months.
On Monday, Afghan special forces killed Sahad Emarati, a senior Daesh commander and destroyed training camps during a firefight in Kot district of the province, said Attahullah Khogyani, a spokesman for the Nangarhar governor.
"We think that Daesh is under pressure," Cleveland said. "As their terrain gets restricted, you see them trying to conduct more external operations and attacks."
(Editing by Raju Gopalakrishnan)