AL-ABER, Yemen -- Forces loyal to Yemen's exiled president, backed by a Saudi-led coalition, launched a major ground offensive against Iran-backed rebels east of the capital Sanaa on Sunday, a military official said.

"This is the largest and fiercest offensive since operations began in Marib province," the official told AFP.

Fighters loyal to President Abedrabbo Mansour Hadi have attacked the rebels in two areas -- Jufeinah and Faw -- that lie on the route leading to rebel-held Sanaa, he said.

Most of the oil-rich province of Marib is controlled by fighters and armed tribes allied with Hadi, but the Shiite Huthi rebels and renegade troops loyal to ousted president Ali Abdullah Saleh hold parts of the province.

The coalition has over the past weeks sent military reinforcements to Marib in preparation for an offensive to retake Sanaa, which was overrun last year by the rebels.

In July, loyalists troops freshly trained and equipped by the coalition pushed the rebels out of the port city of Aden and four other southern provinces. (AFP)