NEW YORK: US troops would not leave Syria as long as Iranian forces its proxies were operting in foreign countries, one of Donald Trump's closest advisors warned on Monday.

The warning from US National Security adviser John Bolton was a clear statement of the White Houses intent to curtail Tehran's influence in Syria and other countries in the region.

Iran was responsible for attacks in Syria, and Lebanon and was responsible for the shooting down of a Russian military aircraft last week, Bolton said.

Bolton said the US would keep a military presence in Syria until Iran is no longer active there.

"We're not going to leave as long as Iranian troops are outside Iranian borders and that includes Iranian proxies and militias," he said.

Both Israel ths US and neighboring Arab countries have all expressed their deep concern about Iran's powerful presence in Syria and how long it plans to stay.

Israel has carried out strikes against many sites in Syria linked to Iranian militias. Last week, it was during an Israeli air raid that Syrian air defenses shot down an aircraft belonging to the Russian military, which is a key supporter of President Bashar Al-Assad.

Bolton on Monday warned Russia that its decision to respond by supplying Syria with an advanced missile defense system would be a "major mistake" and should be reconsidered, AP reported.

"We have American forces in the area we're concerned about," Bolton said. "The Israelis have a legitimate right to self-defense against this Iranian aggressive behavior, and what we're all trying to do is reduce tensions, reduce the possibility of major new hostilities."

Shortly before the downing, Israeli strikes had hit targets inside Syria, reportedly preventing an arms shipment to the Iranian-backed militant Hezbollah group.

Bolton's warning on Iran came as France warned Monday that the Middle East risked “perpetual war” unless a peace agreement can be reached in Syria.

Syrian President “Bashar Assad but also those who support him have a responsiblity to work for a political solution,” French Foreign Minister Jean-Yves Le Drian told reporters at the United Nations.

“If not, we risk heading toward a sort of perpetual war in the area,” he said.

Meanwhile, France has called for stronger international sanctions on Libyans who stand in the way of a political solution in the conflict-ridden country.

The current situation "forces us to show greater firmness toward those who want to insist on the status quo for their sole benefit," Le Drian said, urging sanctions against the "militia members who threaten Tripoli."