GENEVA (Reuters) - The U.N. Syria envoy said on Tuesday that U.S. President-elect Donald Trump was right to seek to work with Russia to beat Islamic State in Syria, but he urged Trump to help push for political reforms to stop the militant group gaining recruits.

U.N. mediator for Syria Staffan de Mistura attends a news conference at the United Nations in Geneva, Switzerland October 6, 2016. REUTERS/Denis Balibouse

Speaking on the BBC’s Hardtalk programme, Staffan de Mistura said it was crucial to fight IS, also known as Daesh, but that a long-term victory required “a completely new approach” to a political solution.

“In other words, some type of political devolution in Syria. Otherwise many other people, unhappy in Syria, may join Daesh while they are fighting Daesh,” he said.

He did not spell out what devolution meant but said it should be the focus of a new U.S.-Russian discussion, and suggested it could lead to an Iraqi-style decentralisation, giving some autonomy to the Kurds and ensuring Sunni Muslims do not feel disenfranchised, while preserving the unity of Syria.

But Anas al-Abdah, president of the opposition Syrian National Coalition, said all sides had accepted that a political transition was the goal for any negotiation.

“Any attempt to slide back on that will be dangerous and counterproductive,” he told Reuters.

“Devolution cannot be the sole entry point to the solution and it certainly cannot replace the key demand of Syrians: that Assad who has murdered hundreds of thousands of his own citizens should step down, and he clearly cannot be part of the transitional period or the future of Syria.”

De Mistura presided over a fitful Syrian peace process in the first half of this year, but it finally stalled because cooperation collapsed between U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov.

Russia has maintained strong support for Syrian President Bashar al-Assad, whom it regards as a bulwark against “terrorists”. The United States has said Assad must leave power under any political transition.

Although the U.N. Security Council has mandated a political transition process, Assad’s government has refused to consider any formula that might involve a dilution of his power.

Many of Trump’s opponents fear that his stated intention to work more closely with Russian President Vladimir Putin means the United States will withdraw support for Syrian opposition groups and agree to Assad’s staying in power.

De Mistura said U.S. priorities had already been discreetly shifting and Assad and his team were probably “feeling comfortable” at the moment, but they should be aware that Russia had no interest in “inheriting” a broken Syria with constant guerrilla warfare for years ahead.

“By the way, President Putin himself has told me ... that he has told President Assad twice: ‘Listen, we are helping you, but there is a moment when we will be expecting you to actually apply a political devolution’,” de Mistura said.