Hassan Rowhani, President of Iran, speaks the United Nations Sustainable Development Summit at the United Nations General Assembly in New York on September 26, 2015.

Iranian President Hassan Rowhani said in an interview Sunday that he is ready to discuss a “plan of action” for Syria’s post-war future after the Islamic State of Iraq and Syria (ISIS) group is defeated.

Iran, which along with Russia is allied with President Bashar al-Assad in the war, has until now been kept out of U.N. diplomatic efforts to piece together a political solution for Syria.

“That is not a problem for us from right now, to start holding discussions and dialogues so as to determine and reach the conclusion of the next plan of action after the terrorists are driven out that territory,” Rowhani said in an interview to NPR radio.

“But we must all act in unison and have a formula that is required to drive out the terrorists, immediately.”

Rowhani is expected to address the crisis in Syria in his speech to the U.N. General Assembly on Monday, after President Barack Obama and Russian leader Vladimir Putin take the podium.

The Iranian leader said his country was ready to discuss “the upcoming options” and added that the Syrian government should be included to “reach a plan of action.”

Tehran has been providing financial and military support to the Damascus regime as well as military advisers on the ground in Syria, where more than 240,000 people have died and four million people have been driven from their homes.

Western powers are seeking to enlist Iran in a new strategy to address the crisis after Russia beefed up its military presence in Syria in a bid to gain the upper hand on the future political transition.

The West has softened its demands for Assad to leave power, signaling that the president could stay on in an interim role as part of a two-stage transition.

Rowhani added that the Syrian people must “have the last word and most important word” on the future of the county, in reference to elections that could cap an interim transition.