Sporadic gunfire rang out in the capital, Juba, overnight as the military "cleared out remnants" of a faction of soldiers accused of mounting a coup attempt, the country's foreign minister said Tuesday amid an ongoing hunt for the former deputy president who is accused of leading the failed plot.

Barnaba Marial Benjamin told The Associated Press Tuesday that the military had arrested five political leaders with suspected links to the coup attempt but that many more were yet to be traced. Chief among the wanted is former Vice President Riek Machar, he said, who is now believed to be in hiding after he was fingered by President Salva Kiir as the politician favored by a faction of soldiers who tried to seize power earlier this week.

"They are still looking for more...who are suspected of being behind the coup," Benjamin said, referring to the military.

Machar, he said, "is wanted by the government." The United States Embassy in Juba and the United Nations Mission in South Sudan denied they are harboring Machar, he said.

The hunt for Machar, an influential politician who is one of the heroes of a brutal war of independence waged against Sudan, threatens to send the world's youngest country into further political upheaval following months of a power struggle between Kiir and his former deputy.

Kiir fired Machar as his deputy in July, sparking fears of political upheaval. Machar, the deputy leader of the ruling Sudan People's Liberation Movement, has said he will contest the presidency in 2015. He has openly criticized Kiir, saying that if the country is to be united it cannot tolerate a "one man's rule or it cannot tolerate dictatorship." At the time of Machar's ouster, part of a wider dismissal of the entire Cabinet by Kiir, the U.S. and the European Union urged calm amid fears the dismissals could destabilize the country.

Kiir, who addressed the nation Monday in combat fatigues he rarely puts on, vowed the plotters would face justice and then ordered a dusk-to dawn curfew in the city. It remains unclear how many people — civilians or soldiers — have been killed or wounded in the latest violence, in which mortar and heavy machinegun fire has been heard. The U.N. Mission in South Sudan reported Monday that hundreds of civilians had sought refuge in U.N. facilities, urging calm and restraint.

South Sudan's government has given little details about how the coup was planned, saying an investigation is under way. But Benjamin said Monday that a group of renegade soldiers attempted to steal weapons from an army barracks in Juba but were then repulsed, sparking gunfights Sunday night and early Monday. Benjamin described the alleged coup plotters as "disgruntled."

The local Sudan Tribune newspaper reported on its website that military clashes erupted late Sunday between members of the presidential guard in fighting that seemed to pit soldiers from Kiir's majority Dinka tribe against those from the Nuer tribe of Machar.

The office of U.N. chief Ban Ki-moon said in a statement that he was "deeply concerned about reports of fighting between members of the (Sudanese military) in Juba and about the risk of targeted violence against certain communities." He urged the country's military leaders to "impose discipline on their forces and to exercise maximum restraint in the use of force."

The oil-rich East African nation has been plagued by ethnic tension since it broke away from Sudan in 2011. In the rural Jonglei state, where the government is trying to put down a rebellion by a former colonel in the country's armed forces, the military itself faces charges of widespread abuses against the Murle ethnic group of rebel leader David Yau Yau. Thousands have been displaced from their homes, many seeking refuge across the border.