Aden -- Saudi warplanes on Friday carried out airstrikes on military sites affiliated with the Southern Transitional Council (STC) in Yemen's southeastern oil-rich province of Hadramout, a local security official said.

The official, speaking on condition of anonymity, said that "several airstrikes targeted positions of the Elite Hadrami security units aligned with the STC."

He said that the strikes occurred one day after Saudi Arabia urged the STC to withdraw its forces from Hadramout, describing the airstrikes as an unprecedented move.

The strikes caused no casualties or damage to military equipment, according to the official.

Residents said that loud explosions were heard in parts of the province, while videos circulated on social media showed plumes of smoke rising from targeted areas following the air raids.

Meanwhile, STC-affiliated media outlets reported that the airstrikes hit their forces in the Ghayl Bin Yamin area of Hadramout.

Saudi Arabia, which backs the internationally recognized government of Yemen, has so far made no official comment on the airstrikes.

Saudi Arabia's Foreign Ministry said on Thursday that recent STC troop deployments in two southern Yemeni provinces constituted an "unjustified escalation" that undermines Yemen's interests and complicates the Saudi-led efforts to restore stability.

Riyadh also announced that a joint Saudi-Emirati military delegation had arrived in Aden to coordinate with the STC on withdrawing its forces in an orderly and timely manner and transferring military camps to government-affiliated or local forces.

Tensions in Yemen escalated on Dec. 3 when STC forces took control of Hadramout following clashes with pro-government units. The STC also criticized the Presidential Leadership Council (PLC) for failing to launch what it described as a serious campaign against the Houthi group.

Yemen has been mired in conflict since 2014, when Houthi forces captured Sanaa and large swathes of the north, prompting a Saudi-led coalition to intervene in 2015.

The STC later expanded its presence into the eastern province of Al-Mahrah without reported resistance and has since recruited local forces in both provinces, despite repeated calls by the Yemeni government and Saudi Arabia for de-escalation.