President Kiir declares immediate ceasefire in S Sudan: State TV

South Sudan's President Salva Kiir has ordered a unilateral ceasefire after days of fierce fighting between troops loyal to President Salva Kiir and rebels backing former vice president, Riek Machar, claimed hundreds of lives in the capital Juba.

According to the reports, Information Minister Michael Makuei at 6:00pm local time on Monday announced on state broadcaster SSBC that President Kiir had issued directives for an immediate cessation of hostilities.

The president has called for the implementation of a peace deal signed between the two sides in August last year, the minister added.

"The president has reiterated his commitment to the continued implementation of the [peace] agreement in letter and spirit, and thus issues an order of cessation of hostilities with immediate effect," the minister said.

However media reports indicate that heavy gunfire was heard in Juba after the order.

This comes as Juba has been mired in fresh fighting since Thursday when troops loyal to Kiir and Machar clashed, raising fears of a return to a full-blown conflict after a two-year lull.

Tanks, helicopter gunships, heavy artillery and mortars have been used in the latest bout of violence.

The United Nations Security Council (UNSC) has voiced alarm over the renewed fighting and surge in violence, which has left at least 270 people dead since Friday and risks plunging the country into a new civil war. The council has also urged both sides to halt the violence and called for the full implementation of the 2015 peace agreement.

In a related development, South Sudan's vice president, and a former rebel chief, called on troops loyal to him to cease fighting after three days of clashes in the capital Juba with forces supporting President Salva Kiir, AFP reported.

"I inform all troops who have been fighting and have been defending themselves that they should observe the ceasefire and stay in position," Machar said on Eye Radio Juba, a short while after Kiir ordered an immediate unilateral ceasefire.

Machar said the ceasefire started at 8:00pm (1700 GMT) on Monday.