"Discussion is very difficult about terrorism group lists and we are trying," Amir-Abdollahian said on the sidelines of the meeting.
Earlier on Friday, 18 foreign ministers of the ISSG started negotiations in New York City. Participants of the talks include UN Secretary General Ban Ki-moon, UN envoy to Syria Staffan de Mistura, Russian Foreign Minister Sergei Lavrov, US State Secretary John Kerry, Arab League and Organization of Islamic Cooperation representatives.
Lavrov has told reporters that the atmosphere at the meeting is "normal."
On Thursday, Kerry said the United States and Russia managed to narrow divisions related to Syrian terrorist designations during talks in Moscow. He underscored that US and Russian differences over the terrorists list would not hinder the Syrian peace process.
World and regional leaders of the ISSG are tasked with drafting a UN Security Council resolution to settle the nearly five-year Syrian crisis, upholding commitments reached at the second ISSG round in November.
The views of Iran and Russia on the list of Syrian terrorist organizations, discussed by the International Syria Support Group (ISSG) in New York, are similar, Iran’s Deputy Foreign Minister said.
"We had some negotiations about terrorist groups list and there is a difference [in] idea who are terrorist groups," Amir-Abdollahian said. "Tehran and Moscow position is close, and we are trying. "
Syria has been mired in civil war since 2011, with Damascus fighting against numerous opposition factions and extremist groups. The international talks on settlement of the Syrian crisis started in October. During the second round of talks in the so-called Vienna format in November, the negotiators called for elections in Syria to be held within 18 months.