(Xinhua) -- Fighting between Yemen's government forces and the Southern Transitional Council (STC) heavily escalated on Saturday in the country's southern province of Abyan, a security official told Xinhua.

According to the Abyan-based security source who asked to remain anonymous, "a prominent military official of Yemen's government forces along with six of his bodyguards were killed during the escalating fighting with STC in Abyan."

He said that the STC's military units fired a heat-seeking missile and killed Brigadier Mohamed Saleh Aqili, commander of the 153rd infantry division, along with six of his bodyguards in Abyan province.

Several other soldiers of the government forces were either killed or injured as fighting heavily intensified with the STC's military units on the outskirts of Zinjibar, Abyan's capital city, he added.

Another military source of the STC's military units confirmed to Xinhua that "Yemen's government forces are desperately seeking to advance into the southern main cities controlled by the STC."

"Our military units are defending their main southern cities and aborted the government's attacks several times during the past days," he said.

He said that nearly five members of the STC's military units were killed in the ongoing fighting taking place near Zinjibar city.

The surge in violence coincided with declaring the southern port city of Aden as an "endemic area" following coronavirus spread and mosquito-borne diseases among the city's citizens.

On April 25, the STC declared a plan to establish self-rule in Aden and other areas under its control, blaming the Yemeni government of intransigence and refusing to implement the Saudi-brokered agreement on southern Yemen.

Yemen's government based in Saudi Arabia's capital of Riyadh had issued an immediate response to the STC's announcement saying it would have catastrophic consequences for the power-sharing agreement.

The Riyadh Agreement was signed in November last year between the elected Yemeni government and the STC, ending months of stand-off between the two sides in Aden.

The main points of the deal include the unification of all military forces under the ministries of interior and defense, and the formation of an efficient government made up equally between the north and south of Yemen.