India, May 26 -- Iran's Revolutionary Guard Corps (IRGC) said on Tuesday that it reserved the "legitimate and definite" right to retaliate against any ceasefire violations by the United States, adding that its air defence units had shot down a US MQ-9 drone.

According to the reports in Iranian media quoted by Reuters, the IRGC also claimed to have fired at a fighter jet that had entered Iranian airspace.

Iran's Supreme Leader, Mojtaba Khamenei, also released a statement on Tuesday, saying that regional countries would no longer be shields for US bases.

He said it in a written statement carried by state television.

"What is certain in this regard is that the hands of time will not turn backwards, and the nations and lands of the region...