Sudanese protesters marched in the capital Khartoum and cities across the country on Thursday amid mounting anger over the October military coup and soaring electricity, fuel and bread prices in its wake.

Billions of dollars in foreign aid were suspended by Western countries and international financing institutions after the October 25 coup and military commanders have yet to appoint a prime minister to tackle the economic crisis.

A UN World Food Programme official told Reuters that almost half of Sudan's population was facing acute hunger, double the estimate of last year. Prices for food and other essential goods can rise over the course of a single day.

The protest movement has gained fresh momentum as citizens begin feeling the crunch of steep hikes in energy and food prices while Sudan's currency has lost a quarter of its value.

"The living circumstances are unbearable, to the point of hunger and the inability to afford medical treatment and education, and so we must remove this regime," said protester Alaa Ahmed, 24, a doctor, as she marched in Khartoum.

"The economic situation is catastrophic. The military has impoverished Sudan," said 55-year-old protester Adil Osman. "We will remain in the street to bring them down."

Thursday's protest was the third and largest this week in the capital. Rallies were also reported in Port Sudan, Gadaref, Atbara, Nyala and elsewhere, unverified social media images showed.

In Khartoum protesters marched to within 400 metres (1312 feet) of the presidential palace, braving heavy tear gas, and a convoy of soldiers wielding clubs could be seen riding towards the protest route, a Reuters reporter said.

The military says the coup was a necessary corrective measure after political infighting and have pledged to hand over power to a government appointed by consensus or elections. Protesters want an immediate exit of the military from politics.