WASHINGTON (Reuters) - A senior U.S. general on Thursday sharply criticized Russia’s deployment of the S-300 surface-to-air missile system in Syria, saying it was a needless escalation and a knee-jerk response to last month’s downing of a Russian military aircraft there.

FILE PHOTO: People watch S-300 air defense missile systems launching missiles during the Keys to the Sky competition at the International Army Games 2017 at the Ashuluk shooting range outside Astrakhan, Russia, August 5, 2017. REUTERS/Maxim Shemetov/File Photo

Army General Joseph Votel, who oversees U.S. forces in the Middle East, said the deployment also appeared to be an effort by Moscow to help shield “nefarious activities” by Iranian and Syrian forces in the country.

U.S. President Donald Trump has ordered bombing of Syria two times since taking office last year in response to what he says was Syria’s use of chemical weapons in that country’s civil war.

Israel has justified its air raids in Syria by saying they are needed to foil deployments and arms transfers by Iran or Lebanon’s Hezbollah guerrillas, both allies of Damascus.

The S-300 deployment “appears to be an effort to cover for Iranian and Syrian regime nefarious activities in Syria. So, again, I think this is a needless, needless escalation,” Votel told reporters at the Pentagon.

Moscow said on Tuesday that it had delivered the S-300 following a decision it took after accusing Israel of indirect responsibility for the downing of a Russian spy plane by Syrian forces as they fired on attacking Israeli jets in September.

Reuters reported in 2015 that Israel had trained against a Russian-supplied S-300 system in Greece. The United States has also been deepening its military cooperation with Greece, a NATO ally. Last month, Greece hosted U.S. General Joseph Dunford, the chairman of the Joint Chiefs of Staff, in Athens.

‘PROBLEMATIC’

Israeli Energy Minister Yuval Steinitz, a member of Israel’s security cabinet, acknowledged that the S-300 deployment was “a problematic matter for us.”

“And it could be for the Americans too. This is a system which certainly makes things difficult for us and requires that solutions be found,” Steinitz told Israel’s Army Radio.

At the same time, Steinitz acknowledged that the technology driving the S-300 was decades old, with systems developed in the 1970s. He said Israel would continue its campaign against Iran in Syria and would overcome the challenges posed by the S-300.

Votel said the U.S. military was aware of the S-300’s capabilities and did not suggest the system’s deployment would halt any U.S. military activities in Syria, where U.S. forces are battling Islamic State militants.

“Our forces here have been operating under a latent anti-air threat for some time and we will continue to do so,” he said. The United States has been ramping up its rhetoric against Iran in recent weeks as it tightens sanctions against the country after pulling out of the 2015 nuclear deal with Tehran.

U.S. Secretary of State Mike Pompeo blamed Iran on Wednesday for threats to American missions in Iraq and said the United States was terminating a treaty of amity with Tehran, which is the target of increasing U.S. sanctions over its missile programs.

Votel suggested that countries in the region had good reason to be concerned about Iran’s activities in Syria.

“We believe they are moving lethal capabilities into Syria that threaten neighbors in the region,” he said.