ADEN: The Saudi-led coalition has deployed newly formed units near Yemen's Marib where battles have abated, according to military and government sources, as the warring sides hold their positions in the fight for energy-rich areas that has led to the war's biggest escalation in years.

The Iran-aligned Houthi movement last month responded to losses in Shabwa and Marib at the hand of Emirati-backed forces with unprecedented assaults on alliance member the United Arab Emirates, dealing a fresh blow to stalled peace efforts.

Marib is vital because it is the internationally recognised government's last stronghold in North Yemen, and the country's sole gas producing region with one of its largest oilfields.

Three military sources said the UAE-backed Giants Brigade, southern Salafi Sunni Muslim fighters, have halted their advance in Marib after penetrating a Houthi cordon around the main city and securing the route to oil-rich Shabwa in the south.

The coalition in January sent the Giants Brigade to main front lines after Houthi advances following years of stalemate, during which the UAE in 2019 largely reduced its presence.

Last week, the alliance deployed new units comprised of northern tribal and Salafi fighters, named the 'Happy Yemen Brigades', near Marib, two government sources said, in a restructuring of local forces battling the Shi'ite Houthis.

The coalition did not respond to a request for comment.

It was not immediately clear if the move paves the way for southern fighters to return to positions on the western coast, but it further weakens the hold of the Islamist Islah Party that had dominated pro-coalition units in Marib.

So far the new brigade has not entered Marib and is battling Houthi forces holding the Harad border crossing area between Yemen and Saudi Arabia that has been shut since 2015, when the coalition intervened in Yemen.

The war is multifaceted with factions under the coalition umbrella vying for power despite being united against the Houthis, who ousted the government from the capital, Sanaa, in late 2014.

Last month's escalation, which once again embroiled the UAE and saw a return of deadly coalition air strikes in Yemen, has renewed international focus on a war that has killed tens of thousands of people and caused a dire humanitarian crisis.

The conflict is largely seen as a proxy war between Saudi Arabia and Iran. The Houthis say they are fighting a corrupt system and foreign aggression.