WASHINGTON (REUTERS) - Threats made by Iran will only further isolate the country, the top US envoy for Iran said on Friday (Jan 17) after Teheran's supreme leader Ayatollah Ali Khamenei said its fight could move beyond its borders.

"As long as the regime threatens the world it will become more isolated," Brian Hook, US Special representative for Iran, told reporters in a briefing.

"Until Iran behaves like a normal nation its isolation will only deepen," he said.

In his first Friday prayers sermon in eight years, Khamenei told worshippers chanting "Death to America" that the elite Revolutionary Guards could take their fight beyond Iran's borders after the US killing of a top Iranian commander.

President Donald Trump in 2018 pulled the United States out of a nuclear deal between Iran and major powers, arguing the agreement was too weak and that new sanctions would force Iran to accept more stringent terms.

Hostilities escalated this month after the United States killed Iran's most powerful military commander in a drone strike in Iraq and Iran retaliated by launching missile strikes at US targets in Iraq.