South24| Xinhua

A new batch of Saudi Arabia's armed forces arrived in the southern port city of Aden amid tension with the local Southern Transitional Council (STC) security units, a military official told Xinhua on Wednesday.

"Saudi Arabia wanted to increase presence through dispatching a new batch of its troops that arrived in Aden late on Tuesday as tension continues in escalation in the strategic city," said an Aden-based military official who asked to remain anonymous.

"Fears mounted from potential attacks and the new forces will be tasked with securing the well-fortified main headquarters of the Saudi forces in Aden," the source said.

Relations between the powerful newly-recruited southern forces of the STC and Saudi Arabia were deteriorated during the past months, the military source said.

There's a wave of growing anger and resentment among the local Yemeni people and some officials against Saudi Arabia that received securing the southern cities following the withdrawal of the United Arab Emirates forces from Aden last year, according to the official.

Last month, security units loyal to the STC were deployed in and around Aden's International Airport and prevented Saudi forces from replacing the Yemeni troops tasked with securing the key navigational facility.

Yemeni military observers believe that the mutual trust between Saudi Arabia and its local allies particularly in the southern provinces is weakening gradually.

Saudi Arabia stopped supporting the newly-recruited southern forces based in Aden and elsewhere in the turbulent neighboring regions, and stopped paying their monthly salaries for unknown reasons, the observers said.

During the past weeks, the newly-recruited southern military forces decided to raise its combat readiness in Aden, citing soaring tension with the government forces backed by Saudi Arabia.

The recent tension is set to escalate after Saudi Arabia prevented senior southern political leaders of the STC from returning to Aden last month.

The STC, a key ally of the Saudi-led Arab coalition, has released a press statement through their media outlets to protest the Saudi statement that the STC "could trigger a devastating popular uprising in the south."

The impoverished Arab country has been locked in a civil war since late 2014 when the Houthi rebels overran much of the country and seized all northern areas including the capital Sanaa.