UN Secretary-General Ban Ki-moon is inviting South Sudan’s president and rebel leader to New York this month in a bid to bolster their struggling peace accord.

UN Secretary-General Ban Ki-moon is inviting South Sudan's president and rebel leader to New York this month in a bid to bolster their struggling peace accord.

Rebel leader Riek Machar is planning to attend the September 29 meeting, his spokesman told AFP, but it remained uncertain that President Salva Kiir would turn up.

The leaders signed a peace deal last month but fighting has continued despite a ceasefire that was due to take hold on August 29.

Ban "hopes it will be attended at the highest level to ensure that the implementation of the agreement receives the fullest possible support from the international community," a UN spokesperson said Tuesday.

Kiir told reporters in Juba earlier that he was "fully committed" to ending his country's war as the UN Security Council was to decide on a new wave of sanctions.

The United States has requested that a global travel ban and assets freeze be imposed on South Sudan's army chief Paul Malong and rebel commander Johnson Olony for their role in the continued fighting.

The sanctions will come into force at 19:00 GMT if no objections are raised by the 15 Security Council members.

The UN meeting to be held on the sidelines of the General Assembly session would include envoys from key neighboring countries as well as the United States, Britain and other European states seeking to end the war.

Last year, Kiir failed to turn up at a meeting on South Sudan also organized during the high-level session of the General Assembly.