Sudan's army has launched a major offensive against the powerful paramilitary group it is fighting in the country's civil war, targeting areas in the capital it lost at the start of the conflict.

In dawn strikes on Thursday, government forces shelled Rapid Support Forces (RSF) bases in the capital Khartoum, and Bahri to its north.

Sudan has been embroiled in a war since the army and the RSF began a vicious struggle for power in April 2023, leading to what the UN has called one of the world's worst humanitarian crises.

Up to 150,000 people have been killed in the conflict while more than 10 million people - about a fifth of the population - have been forced from their homes.

The military escalation comes despite US-led efforts to broker a ceasefire, which is being discussed on the sidelines of the UN General Assembly this week.

Residents of the capital said the artillery and air strikes started overnight and intensified at dawn.

Numerous accounts said the army crossed key bridges over the River Nile - which had separated government-controlled areas in Omdurman from the regions controlled by the RSF.

The RSF claimed to have repelled the attempts, but sounds of clashes and plumes of smoke were reported coming from locations in central Khartoum.

Since early in the war, the paramilitaries have been in control of nearly all of the capital.

Thursday's advances appear to be the government's first significant push in months to regain some territory.

Speaking later at the UN General Assembly in New York, Sudan's de facto leader, Gen Abdel Fattah al-Burhan, said that he supported efforts to bring an end to the war, but only if they brought an end to the RSF's occupation of Sudanese territory.

He questioned why the international community had not stepped in to help counter the group, and accused states in the region of "providing funding and mercenaries for their own political and economic benefit, in flagrant violation of law and international will".

The UN has called for "immediate" action to protect civilians and end the fighting.

It says that, since the start of September, it has documented at least 78 civilian deaths as a result of artillery shelling and air strikes in the greater Khartoum area.

Much of the worst and most intense fighting has taken place in heavily populated regions. Both sides have accused each other of indiscriminately bombing civilian areas.

"Relentless hostilities across the country have brought misery to millions of civilians, triggering the world’s fastest-growing displacement crisis," warned the UN on Wednesday.

It noted that half of the 10 million people who had fled their homes were children, while at least two million have sought protection in neighbouring countries.

It also called Sudan "the world's largest hunger crisis". There are fears of widespread famine as people have not been able to grow any crops.

There have also been warnings of a possible genocide against non-Arabs in the western region of Darfur.

A cholera epidemic is also raging throughout the country- more than 430 people have died from the easily-treatable disease in the past month, the health ministry said on Wednesday.

But getting treatment to those affected areas is hugely complicated by the conflict.