An air-strike by the Saudi-led coalition hit the headquarters of the Special Security Forces on May 27, 2015 in the Yemeni capital Sanaa
Riyadh (AFP) - A Saudi-led coalition is making slow but steady progress five days into a major offensive towards the rebel-held capital of Yemen, a coalition source said Friday.
Giving a rare update on the fighting in Marib province, east of Sanaa, the source told AFP "things are going slowly but surely."
Coalition-supported forces backing exiled President Abedrabbo Mansour Hadi began their push Sunday against the Iran-backed Huthi rebels and allied troops loyal to ousted president Ali Abdullah Saleh.
Taking Marib, in central Yemen, would allow the coalition to move on Sanaa, which the Huthis seized last year.
"The battle will not enter its decisive phase yet," because the coalition seeks to minimise its casualties, the source said.
The bulk of coalition troops are massed about 50 kilometres (31 miles) from Marib city waiting for "zero hour," when they will move on the provincial capital, he said.
In the meantime, the coalition is targeting rebel supply lines to Sanaa and the Huthi stronghold of Saada in the far north.
"Progress occurred this morning north of Marib dam," several kilometres from Marib city, where howitzers, fighter jets and helicopters targeted resistance, the source said.
"The battle to restore Marib is a vital operation because it will be the beginning of a quick end" to the Huthis' control, he added.
Months of coalition air strikes have failed to dislodge the Huthis from territory they had seized in Yemen.
But the insurgents began to lose ground in July when the coalition sent in armour, troops and Yemeni fighters trained in Saudi Arabia.
Riyadh formed the Arab alliance in response to fears the Huthis would take over all of Yemen and move it into the orbit of Sunni Saudi Arabia's Shiite regional rival Iran.
An analyst has estimated the coalition has more than 5,000 troops in Yemen, supporting local forces.
The Marib offensive began after an early-September missile strike on a coalition base in the province killed 67 coalition soldiers, including 52 from the United Arab Emirates.
The United Nations says nearly 4,900 people have been killed since late March in Yemen, where the UN aid chief has called the scale of human suffering "almost incomprehensible."