Iran's relationship with al-Qaeda began during the Osama bin Laden era and continued after his death with the hosting of his family.
'We are chasing ISIS,' an Afghan National Army commander said. 'Wherever it rises up, we will kill it.'
A roadside bomb hit a bus in Farah, killing mostly women and children, while gunmen stormed a building in Jalalabad while officials were meeting with foreign aid agencies.
The blast coincided with the return to Afghanistan of First Vice President Abdul Rashid Dostum, who narrowly escaped the attack.
More Afghans died in the first six months of 2018 than in any other year during the same period since the UN began keeping records. ISIS was responsible for 52% of the casualties suffered in suicide and 'complex' attacks, while 40% are attributed to the Taliban.
Afghan security forces killed two gunmen who attacked a provincial education department compound a day after an ISIS suicide bombing rocked the city, officials say.
The attack comes a day after US Secretary of State Mike Pompeo expressed 'hope' for peace talks between the Afghan government and Taliban.
An ISIS suicide bomber killed 19 people and wounded 21 others in Jalalabad over the weekend.
The 'Islamic State of Iraq and Syria' (ISIS) claimed responsibility for the attack, which comes before the start of a unilateral cease-fire declared by the Afghan government with the Taliban.
The explosion took place about an hour after the Ulema Council issued a fatwa declaring suicide attacks to be haram and urging the Taliban to join the peace process.