BRUSSELS (Reuters) - The U.S. withdrawal from the Iran nuclear deal opens the way to raising pressure on Tehran to stop its military support for Syrian President Bashar al-Assad and leave the country, a Syrian opposition leader said on Thursday.

FILE PHOTO: Nasr al-Hariri, Head of the opposition Syrian Negotiation Commission (SNC), speaks in Brussels, Belgium, February 20, 2018. REUTERS/Francois Lenoir/File Photo

Nasr Hariri of the Syrian Negotiation Commission (SNC) spoke in the EU political hub Brussels as Assad declared separately that U.S. forces should leave Syria because people in the Middle East were tired of foreign invasions.

Hariri pushed back against Assad’s comments, stressing that Russia and Iran had been fighting on behalf of Assad in the Syrian war, helping him retake considerable territory from rebels and Islamic groups. Hariri said there were now up to 100,000 Iranian or Iran-affiliated fighters in the country.

“The role of Iran is getting bigger and bigger, at the expense of our people,” Hariri said. “So we are supporting any international mechanism that could limit the influence of Iran in the region in general, and in our country in particular.”

“We cannot separate one from another, the (Iranian) nuclear program from Tehran’s missile program and Iran’s malign behavior in our region,” he said.

Earlier in May, U.S. President Donald Trump walked away from the 2015 international nuclear accord under which world powers lifted some economic sanctions on Iran in exchange for curbs on its disputed atomic energy program.

The EU is now scrambling to keep the deal alive because it sees it as a key element of international security.

But some EU states also share Trump’s anger with Iranian military involvement across the Middle East, including in Yemen, and would want to limit Tehran’s missile capabilities as well.

Hariri had talks with EU foreign policy chief Federica Mogherini about the matter on Thursday.

“While Iran and Iranian militias are present in our country, there will not be a political, negotiated solution. There will not be a solution while these foreign partners are there. We are looking for ways to force Iran out of Syria,” he said.

With Moscow and Tehran behind him, Assad now seems unassailable in a war that has killed half a million people, uprooted around 6 million inside Syria and driven another 5 million abroad as refugees - including to the EU.

But Hariri said three years of deepening Russian military intervention were still not enough to secure a decisive victory for Assad and that Damascus could still lose if Moscow withdrew.

“The rumor that the regime has won the war are not true. Based on the current situation, the regime cannot claim any stable victory,” Hariri said. Russia, he added, should get serious about international peace talks if it wants a way out.

The EU also strongly supports U.N.-led peace talks on Syria but they have made scant progress since conflict first erupted there in 2011, largely because the Russia and the United States are backing opposing sides in the war.