Mali is on the brink of a major humanitarian disaster following a coup and rebellion in the north, Amnesty International says.
The human rights group says aid agencies must be allowed immediate access to the country, to prevent more civilians dying.
Some fighters in the north have said they have stopped military operations.
But Amnesty says all food supplies and medicines stored by aid agencies have been looted and most workers have fled.
"The population is at imminent risk of severe food and medical shortages that could lead to many casualties, especially among women and children who are less able to fend for themselves," Amnesty's West Africa researcher Gaetan Mootoo said in a statement.
The group said the three northern towns of Gao, Kidal and Timbuktu have experienced days of looting, abductions and chaos.
The Tuareg separatist rebels of the Azawad National Liberation Movement (MNLA) said in a statement on their website that they had captured enough territory to form their own state.
But the position of Islamist insurgents, who fought alongside the Tuareg in northern Mali, is unclear.
'Abductions and rapes'
The Algerian government says seven of its staff have been kidnapped by unknown gunmen in the northern city of Gao, which is in rebel hands.
The consul and six colleagues were forced to leave their diplomatic mission at gunpoint. The Algerian government says it is doing all it can to find them.
Journalist Martin Vogl in Bamako says the situation in the northern town of Gao is particularly tense - and people are continuing to flee the north.
Buses to the capital have been packed and people are desperate to get out, even jumping onto the backs of transport trucks, he says.
Amnesty says women and girls are being abducted from their homes in Gao and Menaka, another northern town, and there are reports that some have been raped.
"Women and girls particularly are too terrified to leave their homes. People are describing an atmosphere of near total lawlessness," Amnesty's Gaetan Mootoo said.
Meanwhile the regional mediator with the rebels, Burkina Faso's Foreign Minister Djibrill Bassole, said he was hopeful sanctions could soon be lifted.
Speaking on local television after meeting the coup leader Capt Amadou Sanago in the Malian capital Bamako, he said an announcement in "the right direction" could be expected soon.
"We are going to do everything so that these sanctions are not only suspended but completely removed. We are getting there," said Mr Bassole. He added that Capt Sanago had "the right attitude".
The sanctions were imposed by neighbouring countries in an effort to force the coup leaders to hand over power.
Mali's junta seized power last month, saying that the civilian government had been too soft on the rebels.
But the MNLA and the Islamist group Ansar Dine took advantage of the military being distracted to take control of the whole of northern Mali, including the historic city of Timbuktu.
On Wednesday, the UN Security Council called for an end to the fighting in Mali - a request heeded by the MNLA.
"After the complete liberation of the Azawad territory and given the strong request by the international community", the MNLA "decides unilaterally to declare the end of military operations from midnight Thursday", a statement on the group's website says.
In New York, the Security Council said it "strongly condemns the continued attacks, looting and seizure of territory carried out by rebel groups in the north of Mali and demands an immediate cessation of hostilities".
The UN also voiced alarm at the presence of Ansar Dine, which has links to al-Qaeda and wants to impose Islamic law, or Sharia, across the whole of the West African state.
Unlike the MNLA, Ansar Dine is not in favour of an independent northern state.
The MNLA was formed last year, partly by well-armed Tuareg fighters returning from Libya, where they had backed former leader Muammar Gaddafi.
The UN also backed the efforts of the Economic Community of West African States (Ecowas) to restore order in Mali.
Mali's borders have been closed to trade, the country's access to funds at the central bank for the region's common currency frozen and travel bans slapped on coup leaders and their supporters.
The coup and Tuareg rebellion have exacerbated a humanitarian crisis in Mali and some neighbouring countries, with aid agencies warning that 13 million people need food aid following a drought in the region.
The International Committee of the Red Cross says it is attempting to open a dialogue with the rebels so that it can recommence its aid operations in remote parts of the north.
It said it had had to withdraw its international staff after its warehouses were looted in the northern town of Gao, which has been seized by the rebels.