Iraqi Kurdish leader Masoud Barzani denounced an international anti-ISIS conference for its failure to invite representatives of Iraq’s Kurdistan region, despite determined Kurdish resistance to the terrorists also known as the Islamist State group. Barzani, the president of Iraq’s autonomous Kurdistan region, said Kurdistan deserved to be present at the talks in London this week aimed at coordinating the international response against the group.

“I express my and Kurdistan people’s disappointment with the organizers of this conference, and it is unfortunate that the people of Kurdistan do the sacrifice and the credit goes to others,” said Barzani, in a statement reported by Kurdish news site Rudaw on Friday. “The people of Kurdistan bear the brunt of this situation, and no country or party can represent or truly convey their voice in international gatherings.”

U.S. Secretary of State John Kerry and British Foreign Secretary Philip Hammond co-hosted the anti-ISIS conference in London Thursday with 21 coalition member countries, including Iraq, Saudi Arabia and Turkey. Kerry claimed the Iraqi government and its international backers had made significant progress in the struggle against the terrorist group, saying that several thousand ISIS fighters had been killed, according to the Guardian. Iraqi Prime Minister Haider al-Abadi also appealed for continued Western military support in the fight.

The conference took place as Kurdish forces reported cutting off one of ISIS’s key supply lines to Mosul, the major Iraqi city seized by the militant group in June, reported the Washington Post. Kurdish authorities claimed that 200 ISIS fighters were killed in the Thursday assault, which Iraqi national security forces were reportedly not involved in coordinating. Barzani has argued that Kurdish peshmerga forces “are the most effective force countering global terrorism today.” The force is widely seen as crucial to preventing ISIS’s continued expansion across the region.