(Adds detail, background)

BEIRUT, Sept 28 (Reuters) - Foreign states have given Syrian rebels surface-to-surface Grad rockets of a type not previously supplied to them in response to a major Russian-backed offensive in Aleppo, a rebel commander told Reuters on Wednesday.

The Grad rockets with a range of 22 km and 40 km have been supplied in "excellent quantities" and will be used on battlefronts in Aleppo, Hama and the coastal region, rebel commander Colonel Fares al-Bayoush said.

While Grad missiles have previously been supplied to rebels, Bayoush said it was the first time this particular type had been delivered. Each salvo contains 40 rockets, he said, without giving further details. The rebels had previous stocks of the rocket captured from army stores, he added.

Bayoush added that there was as yet no sign of the rebels being supplied with anti-aircraft missiles they have demanded.

A video posted on YouTube on Monday showed Free Syrian Army rebels firing Grad missiles at government positions near Aleppo. Bayoush confirmed the weapons being fired in the video were newly supplied.

Rebel groups fighting under the Free Syrian Army banner have received military aid from states opposed to President Bashar al-Assad via a U.S.-backed coordination centre in Turkey.

The rebellion's foreign backers have previously supplied Russian-made Grad rockets to the rebels: rockets with a 20 km (12 mile) ranges were delivered earlier this year in response to an earlier offensive in Aleppo, rebels told Reuters at the time.

(Reporting by Tom Perry; Editing by Andrew Heavens) ((thomas.perry@thomsonreuters.com; Reuters Messaging: thomas.perry.reuters.com@reuters.net))