Yemeni officials say Saudi Arabia is increasing its military presence in southern Yemen, airlifting in additional troops, armored vehicles, tanks and other military equipment.
The deployment comes as the United Arab Emirates, Saudi Arabia's main partner in the war in Yemen, continues withdrawing troops from the country.
The UAE pullout leaves the Saudi-led coalition that's fighting Yemen's Houthi rebels with a weakened ground presence and fewer tactical options.
On Thursday, Yemeni officials said 15 Saudi military transport aircraft landed in the southern port city of Aden.
The Yemeni officials say additional Saudi troops arrived by land in two other key Yemeni provinces, Shabwa and Hadramawt. They spoke anonymously to brief reporters.
Saudi Arabia has been stepping up reinforcements since August, following violent infighting among Yemeni forces within the anti-Houthi alliance.