Iran has warned the United States against violation of its borders, with parliament speaker Ali Larijani threatening a stronger reaction, a week after Tehran shot down a US drone.
"The downing of their drone was a good experience for them to avoid any aggression against our borders," the semi-official Tasnim news agency quoted Larijani as saying.
"Iran's reaction will be stronger if they repeat their mistake of violating our borders."
Iran said the unmanned US aircraft was in its air space, which Washington denied. Trump ordered retaliatory air strikes but called them off at the last minute, later saying too many people would have died.
The rhetoric between the sides has heated up, with Trump this week threatening Iran's "obliteration" after President Hassan Rouhani on Tuesday called the White House's actions "mentally retarded".
On Wednesday, Trump said any war between Iran and the United States would be swift, but reiterated his desire to avoid a military confrontation even while blasting Tehran's leaders.
