KHARTOUM - Sudan government has set July 26 as the date for signing a deal on power-sharing between South Sudanese rivals, amid concerns that differences may rise to fail the proposed deal.

Sudan's Foreign Ministry on Sunday announced that invitations have been sent to all heads of state of the Inter-Governmental Authority on Development in Africa to attend the signing ceremony in Khartoum next Thursday, Sudanese Media Center reported.

The parties were scheduled to sign the initial deal on July 19, but the signing was delayed at the request of South Sudanese government, who said it needed more time for further consultations.

Sudan's Foreign Minister Al-Dirdiri Mohamed Ahmed was quoted as saying that the Sudanese mediation efforts are supported by the IGAD Chairman and Ethiopian Prime Minister Abiy Ahmed, to complete the remaining tasks of peace realization in South Sudan.

"The opportunities of success provided for these talks are considered enough and make us confident that matters are pressing ahead," he said.

However, South Sudanese conflicting parties have reportedly expressed reservations over the draft document of the deal on power-sharing.

To this end, Sudanese media outlets earlier quoted South Sudan's Information Minister Michael Makuei Lueth as saying that the Sudanese mediation has amended what the parties have agreed on and presented new proposals discussed before.

The South Sudanese opposition alliance has also reportedly expressed objection to the draft agreement and filed a memo with reservations to the mediation.

Abdul-Khaliq Mahjoub, a Sudanese political analyst, expressed concern over possibility that the signing on the power-sharing deal may fail.

"It is apparent that there are deep differences over the items of the agreement that may cripple the endeavors to reach a consensus formula," he said.

The draft deal on power-sharing includes appointment of five vice presidents in addition to other security and governance aspects.

Since June 25, Khartoum has been hosting direct talks between South Sudanese government, rebels and representatives of other South Sudanese opposition groups.

On June 27, South Sudanese President Salva Kiir and rebel leader Riek Machar signed a cessation of hostilities agreement in Khartoum, which included immediate cease-fire and a pre-transitional period of 120 days that went into effect as of the day the agreement was signed.

South Sudan has been suffering from a civil war since December 2013 between the forces loyal to South Sudan President Salva Kiir Mayardit and former Vice President Riek Machar.