Iran's Revolutionary Guards say they have fired missiles at eastern Syria targeting the ringleaders of the deadly attack on a military parade in Ahvaz.

A statement said "many terrorists" were killed or injured in the strikes.

Iranian state television suggested that the missiles hit an area close to the border town of Albu Kamal where Islamic State militants are known to operate.

IS and ethnic Arab separatists from Ahvaz both claimed the 22 September parade attack, in which 25 people died.

The Iranian government has alleged that the assailants were jihadist separatists supported by Gulf Arab allies of the United States.

US Defence Secretary Jim Mattis has dismissed the allegation as "ludicrous".

The Revolutionary Guards announced that its aerospace forces' missile unit had "targeted a base of the ringleaders of Ahvaz terrorist crimes to the east of the Euphrates [river] in Syria with a number of surface-to-surface ballistic missiles" at 02:00 on Monday (22:30 GMT on Sunday).

In addition to causing casualties among the militants, the strikes also reportedly destroyed infrastructure and ammunition stockpiles.

"Our iron fist is prepared to deliver a decisive and crushing response to any wickedness and mischief of the enemies," the statement added.

The Revolutionary Guards did not say where in western Iran the six missiles were launched, but revealed that they travelled a distance of 570km (354 miles).