The top external security advisor to United States President Barack Obama has criticized South Sudanese rebels and the government, saying the latter has “squandered its legitimacy” and “subverted democracy.”

The White House published a video message by National Security Advisor Susan Rice recorded yesterday, in which she refers to massive widespread violence and human rights abuses in Souh Sudan. The video appeared to have been published to coincide with South Sudan's independence day.

In the video, Susan Rice accuses the two warring party leaders Riek Machar and Salva Kiir of greed and power-hunger.

“President Kiir and Riek Machar and their cronies are personally responsible for this new war and self-inflicted disaster... President Kiir and Riek Machar whould rather haggle over personal power and wealth than agree on solutions.”

“Over the past 19 months the government has abdicated its responsibilities, failed to protect its citizens and squandered its legitimacy. Instead of negotiating a resolution to the conflict it has subverted democracy and unilaterally extended its mandate,” said Rice.

She was referring to a constitutional amendment passed by South Sudan's national parliament earlier this year to extend the legal mandate of the president and other national officials for three years beyond 8 July 2015.

Later in her message, Rice urged the estabishment of “a transitional government that can serve with legitimacy and represent the needs of the people of South Sudan.”

This is not the first time the US government has criticized the South Sudanese government, but it is the first high-level statement for a long time following mixed signals from the White House earlier this year. Earlier this year it was reported that Rice was blocking international diplomatic efforts to impose a weapons import ban on South Sudan, according to Foreign Policy website.

In spite of her earlier reported opposition to the weapons ban, Rice is part of a group of Washington officials who have been vaguely threatening to impose 'sanctions' such as bank freezes and travel bans on South Sudanese warlords who perpetrate violence or block peace efforts.

Philippe Bolopion, the UN representative for Human Rights Watch, told Foreign Policy, “The threats are getting old and harder to take seriously now. They have been threatening to impose sanctions for a long time.”