The United Nations says Secretary-General Antonio Guterres is appealing for “calm and restraint” in Sudan after the army ousted President Omar al-Bashir on Thursday.

UN spokesman Stéphane Dujarric said in statement extended to Radio Tamazuj that Guterres continues to follow the developments in Sudan very closely and that he reiterates call for calm and utmost restraint by all.

Dujarric said the UN chief recalls his previous encouragement and expectation that the democratic aspiration of the Sudanese people will be realized through an appropriate and inclusive transition process.

The Secretary-General, according to the spokesman, reaffirms that the world body stands ready to support the Sudanese people as they chart a way forward.

On Thursday, Sudan's President Omar al-Bashir was ousted and arrested by the military after nearly 30 years in power.

Speaking on state TV, defence minister Awad Ibn Ouf said the military would oversee a two-year transitional period followed by general elections.

However, protesters vowed to stay on the streets despite a curfew imposed by the new military authorities. The protesters reject a military-led transitional council.

The military takeover came after months of anti-government protests that escalated this week when thousands of demonstrators began a sit-in outside the army headquarters in Khartoum.

Demonstrations against Bashir, who seized power in 1989 after a military coup, started in December last year.