US soldiers sent to South Sudan

US President Barack Obama has sent 45 US soldiers to South Sudan to protect its nationals and embassy there amid the African nation's volatile security situation.

In a letter sent to Congress Thursday, Obama said the troops left for South Sudan Wednesday, and would remain there until the situation improves, reported Xinhua.

Meanwhile, more US citizens were evacuated from South Sudan Thursday, as government troops and rebel forces continued to clash.

A private charter flight lifted some 130 people from capital Juba, among whom were US citizens and nationals of other countries, State Department Spokeswoman Marie Harf told a regular news briefing.

She said a small number of Americans also flew out of the country aboard a British military aircraft.

A day earlier, Washington airlifted three groups of American nationals, including non-emergency diplomatic personnel, US citizens and third-country nationals, out of South Sudan.

Since fighting broke out Sunday between forces loyal to President Salva Kiir and his former deputy Riek Machar, who was removed from office in July, some 450 people have been killed in clashes so far in Juba.

Machar has rejected Kiir's offer for talks, calling instead for the president's removal by the ruling party and the army.

Kiir accused Machar of orchestrating a military coup against him and declared Monday a state of emergency in the country.