U.S. officials expressed sorrow over the shoot-down of a Russian military surveillance plane off the Syrian coast and said it would not affect the U.S. campaign against Islamic State (IS) fighters.
The comments on September 18 came as Russian officials said that Syrian antiaircraft forces brought down the Il-20 plane inadvertently, but also blamed Israel for conducting a fighter jet raid on Syrian forces at around the same time.
U.S. officials said U.S. forces were not involved in the incident.
Secretary of State Mike Pompeo issued a statement expressing sorrow for the shoot-down, which killed 15 Russian servicemen. He also criticized Iran, which has reportedly shipped sophisticated weaponry to the Hizballah fighters in Lebanon.
Israel has struck targets in both Lebanon and Syria, seeking to thwart Hizballah's ambitions.
U.S. Defense Secretary Jim Mattis, meanwhile, told reporters that the shoot-down complicates relations between Syria and Russia but would have "no effect whatever" on the U.S. campaign to defeat the extremist group IS in Syria.
Mattis also said the incident was a reminder of why the United States supports the United Nations' effort to end the seven-year civil war.
President Donald Trump also expressed concern about the downed Russian plane, calling it a "very sad thing" and "not a good situation."
Earlier, Russian President Vladimir Putin warned Israel against conducting air raids on Syria.
And Israeli Prime Minister Benjamin Netanyahu called Putin to express sorrow over the plane's loss but insisted that Syria bore responsibility.
With reporting by AP and Reuters