RNA - Qassemi made the remarks in a meeting with Norwegian and Swedish ambassadors to Tehran.
"At the meeting, it was announced that Iran was ready for comprehensive and expansive cooperation, including in security areas and implementation of joint fact-finding investigations, with Norway and Sweden," the Iranian foreign ministry spokesman said.
The meeting was held after an armed attack against a military parade in the Southern Iranian city of Ahvaz on September 22. Claimed by the al-Ahwaziyeh terror group, the attack killed 25 people, including a four-year-old child.
Qassemi underlined the importance of accepting the responsibility by Norway, Sweden, and Denmark to confront terrorism, and said, "We do not accept sheltering those who have officially claimed responsibility for the attack."
The meeting also focused on the recent accusations leveled by Denmark against an Iranian diplomat.
During the meeting, Qassemi reiterated Iran's strong objection and dismissal of the accusations made against the country by Israel through machinations and devising of clumsy scenarios.
In relevant remarks on Friday, Iranian Foreign Minister Mohammad Javad Zarif in a phone conversation with his Danish counterpart Andres Samuelsen rejected recent allegations that Iran's intelligence service "had tried to assassinate a dissident" in Denmark, stressing the European state's responsibility to fight al-Ahwaziyeh terrorist group whose leaders have been sheltered in the country.
During the phone conversation, Zarif referred to the clear attempts by Israel to distort relations between Iran and the European states, and underlined Tehran's preparedness to cooperate with the Danish security officials to clarify different aspects of the plot and the reality.
He also reminded the Danish government of its responsibility to prosecute and arrest members of Ahwaziyeh terrorist group which has admitted the responsibility for a terrorist attack in Southwestern Iran in September, describing Copenhagen's support for the group as "unacceptable".
According to Fars News Agency, Samuelsen, for his part, reiterated his country's support for the 2015 nuclear deal and companionship with Europe in using financial mechanisms to continue economic cooperation with Iran.
Without providing any evidence, the Danish police on Tuesday linked so-called Iranian intelligence officers to attacking a person in the country. Denmark's foreign ministry then announced in a statement that it had summoned Iran's Ambassador to Copenhagen Morteza Moradian to Denmark's foreign ministry in that connection.
In relevant remarks on Wednesday Zarif blamed the Israeli spy agency, Mossad, for masterminding false-flag operations against Tehran.
"Mossad’s perverse and stubborn planting of false flags (more on this later) only strengthens our resolve to engage constructively with the world," Zarif wrote on his Twitter page.
Also, on Wednesday, the Iranian foreign ministry summoned the Danish ambassador to Tehran over his country's allegations.
26 people were killed and 69 others were wounded in an attack by al-Ahwaziyeh terrorist group during the nationwide military parades in Ahwaz on September 22.
The terrorists attacked the bystanders watching the annual Armed Forces' parades, marking the start of the Sacred Defense Week, commemorating Iranians' sacrifices during the 8 years of the Iraqi imposed war on Iran in 1980s, in disguise of the Islamic Revolution Guards Corps (IRGC) and Basij (volunteer) forces, killing and wounding several people, including innocent women and children.
None of the officials participating in the military parades in Ahwaz city in Khuzestan province was injured in the attack.