ADEN, Yemen, Dec. 16 (Xinhua) -- Saudi Arabia has suspended the issuance of permits for ships to enter the port of Aden in southern Yemen, amid heightened political and military tensions, a local official from Yemen's Ministry of Transport said on Tuesday.

The official, who spoke on condition of anonymity, said the suspension affects the Aden port, which is controlled by the Southern Transitional Council (STC), but stressed that the motives behind the move remain unclear.

"The suspension has continued for the third consecutive day without any official explanation," the official said, adding that there are "no clear indications about the reasons for this decision."

He noted that it remains uncertain whether the measure is intended as temporary pressure on the STC or represents a longer-term policy shift.

The port of Aden is a critical lifeline for Yemen, facilitating the import of food, fuel and medical supplies for millions of people across the conflict-ravaged country, including northern areas under the control of the Houthi group. Any disruption to port operations could have severe humanitarian consequences, the official warned.

"This port serves the entire country," he said. "The suspension of ship permits may badly affect the flow of essential goods to civilians already suffering from years of war."

The move comes as STC continues to expand its military presence in several strategic provinces, defying repeated calls by the internationally-recognized government to withdraw its forces from Hadramout and Al-Mahrah, a military official told Xinhua.

According to the military official, the STC has shown no indication of reversing its moves, despite local and regional mediation efforts, particularly from Saudi Arabia, which dispatched a senior delegation to Hadramout in recent days in an attempt to de-escalate tensions. However, the efforts failed to halt the deployment, and Saudi forces later withdrew from Aden as the STC pressed ahead with its plans.

The STC has justified its recent military moves by accusing some pro-government factions of maintaining ties to the Muslim Brotherhood, while also criticizing Yemen's Presidential Leadership Council (PLC) for what it described as a failure to launch a serious campaign against the Houthi group, which continues to control northern provinces, including the capital Sanaa.

During the past hours, STC military spokesman Mohamed al-Naqeeb said that new military units had been deployed to the Hadramout Valley and adjacent desert areas as part of security operations aimed at preventing infiltration by Al-Qaeda militants.

According to al-Naqeeb, the Sir Valley's complex terrain -- characterized by mountains, plateaus, wide agricultural plains and vast uninhabited areas -- has made it a favorable environment for militant activity. He added that the Hadrami Elite Forces were continuing to reinforce security measures to maintain stability across key districts in Hadramout.

On Monday, the STC also announced the launch of a military operation in the southern province of Abyan, which has largely been under its control since 2019. The operation was described as targeting militant supply routes and aimed to curb the movement of Al-Qaeda fighters through mountainous and valley regions.

Following its recent takeover of Hadramout and Al-Mahrah, the STC has consolidated military control over eight southern provinces, including Aden and the strategic island of Socotra.

A security official from Yemen's Interior Ministry based in Aden said that terrorist groups in southern Yemen are, for the first time, facing what he described as "a serious and effective confrontation by local Yemeni forces."

While acknowledging the expulsion of government-affiliated military units, the official argued that unified military control under a single authority has contributed to curbing Al-Qaeda activity and cutting smuggling routes, calling it "a positive factor for local and regional stability."

"So far, the STC has faced no regional or international pressure, as its recent actions have been widely viewed as effective in countering terrorist threats," the official said anonymously.

Although the STC is formally part of the UN-recognized Yemeni government, it continues to advocate for the secession of southern Yemen. Founded in 2017, the council seeks to restore an independent southern state, reversing Yemen's 1990 unification between the former North and South Yemen.

Last week, PLC chief Rashad al-Alimi said that unilateral actions by the STC threaten the unity of security and military decision-making and undermine the authority of the internationally-recognized government. He called on the international community to adopt a unified and clear stance rejecting unilateral measures and any challenge to the government's powers.

Yemen has remained mired in conflict since 2014, when Houthi militants seized control of the capital Sanaa, prompting a Saudi-led coalition to intervene the following year in support of the internationally-recognized government. Enditem