The main airport in the capital Khartoum has been the site of heavy fighting and is under the control of the paramilitary Rapid Support Forces (RSF) that is battling the army.
Some evacuations are taking place from Port Sudan on the Red Sea, an 850 kilometre (530 mile) drive from Khartoum.
Here is an overview of what various nations were doing Sunday in efforts to take stranded citizens to safety.
Saudi Arabia led the first reported successful evacuation with naval operations picking up more than 150 people including foreign diplomats and officials from Port Sudan on Saturday.
Riyadh announced the “safe arrival” of 91 Saudi citizens and around 66 nationals from 12 other countries — Kuwait, Qatar, the United Arab Emirates, Egypt, Tunisia, Pakistan, India, Bulgaria, Bangladesh, the Philipines, Canada and Burkina Faso.
On Sunday, the US military sent three Chinook helicopters to evacuate American embassy staff from Khartoum. More than 100 US forces took part in the rescue to extract fewer than 100 people, which saw the choppers flying from Djibouti to Ethiopia to Sudan, where they stayed on the ground for less than an hour.
US Secretary of State Antony Blinken said he ordered the evacuation of staff and their families due to the “serious and growing security risks” amid fighting that has already left hundreds dead and thousands wounded.
Several thousand US citizens including dual nationals are thought to remain in the country.
France launched a “rapid evacuation operation” for its citizens and diplomatic staff, with some 250 French nationals believed to be in the country.
Other European citizens and those from “allied partner countries” would also be assisted, the foreign ministry said without giving further details.
The British army has evacuated UK embassy staff and their families from Sudan, Prime Minister Rishi Sunak said.
“UK armed forces have completed a complex and rapid evacuation of British diplomats and their families from Sudan, amid a significant escalation in violence and threats to embassy staff,” Sunak tweeted.
Ankara began operations at dawn on Sunday, taking some of its estimated 600 nationals by road from two Khartoum districts and the southern city of Wad Madani.
But plans were postponed from one site in Khartoum after “explosions” near a mosque designated as the assembly area, the embassy said.
EU, Germany, Italy, Greece, Netherlands
The European Union said Friday it was “trying to coordinate an operation to get our civilians out of the city which is now in a high-risk situation.” Seven EU members have missions in Sudan.
Italy said it would try to evacuate citizens on Sunday and was “working on a window of opportunity” to get them out, according to Italy’s AGI news agency.
The Dutch Foreign Ministry said it was “participating in an international evacuation operation”, with Foreign Minister Wopke Hoekstra saying teams would “do their utmost to collect Dutch people as quickly and safely as possible”.
Berlin aborted an evacuation attempt for its citizens from Sudan on Wednesday, according to German weekly Der Spiegel. Three military transport planes, which would have carried around 150 German citizens, headed for the country but were made to turn back, it said.
Greek Foreign Minister Nikos Dendias said Sunday that Prime Minister Kyriakos Mitsotakis had ordered to relocate Air Force aircraft and troops to Egypt to participate in a potential operation to rescue Greek and Cypriot citizens from Sudan.
Jordan, Iraq, Lebanon, Libya
Jordanian foreign ministry spokesman Sinan Majali said Saturday that Amman had begun the evacuation of some 300 Jordanian citizens, adding there was “continuous cooperation with the UAE and Saudi Arabia for this purpose”.
Iraqi embassy staff left Khartoum on Saturday, foreign ministry spokesman Ahmed al-Sahhaf said, while on Sunday, 14 citizens arrived safely at a “secure site” at Port Sudan.
Lebanon said 60 citizens had also left Khartoum by road and were “safe”, ahead of their planned evacuation by sea.
The Libyan embassy in Khartoum on Friday said it had evacuated 83 Libyans from Khartoum, taking them to Port Sudan.
China, Japan, South Korea, Indonesia
Other foreign countries preparing evacuations include South Korea and Japan, who have deployed forces to nearby countries.
The Sudanese army has said it is also coordinating efforts to evacuate diplomats from China.
Indonesia said 43 citizens were sheltering inside the embassy compound in Khartoum. ref. AFP