A charity says more than 1,500 people are still missing in Sierra Leone’s capital and the death toll from mudslides and flooding will continue to rise.
People have been gathering at a morgue containing 270 bodies in Freetown, desperate for news of loved ones.
Authorities say at least 300 are feared to have died in a massive mudslide on the outskirts of the city.
Rescue operations continued on Tuesday, a day after victims were trapped under tons of mud as a hillside collapsed.
The British government has said it was ready to help.
A mass burial was expected to take place on Tuesday to free up more space in the overwhelmed central mortuary.
President Ernest Bai Koroma asked residents of Regent and other flooded areas in Freetown to leave their homes so military personnel and other rescue workers could search for survivors.
Up to 3,000 people are said to have been left without shelter after floodwaters smashed through their homes amid heavy rain.
Aid agencies said there were immediate concerns for thousands of people in the capital, who may not have access to water that is safe to drink.
ActionAid’s Humanitarian Director, Richard Miller, said: “While search and rescue is still ongoing, there are currently over 1,500 people reported missing – and this number is expected to rise.
“Our local aid workers in Sierra Leone are telling us that they are especially concerned for the welfare and safety of girls and women, who are the most vulnerable at this time.
“We are working closely with them and other aid agencies to reach people in need as quickly and effectively as possible.”
The UK Government, which has an ongoing presence in Sierra Leone through the Department for International Development, said it has been investing in helping Sierra Leone prepare for disasters and responding to emergencies since the end of the Ebola crisis.
Sky News understands representatives from the UK are meeting officials in Sierra Leone to find out what help, if any, the Government of Sierra Leone requires.
A UK Ministry of Defence spokesperson said: “A small number of UK personnel from the International Security Advisory Team in Freetown are assisting the Government of Sierra Leone in their response to the mudslide.”
International Development Secretary Priti Patel said: “I am deeply saddened by the devastating landslides and flooding in Freetown, Sierra Leone which have claimed innocent lives. My thoughts are with all those affected at this tragic time.
”From stopping the Ebola outbreak in its tracks to helping the country rebuild after this deadly disease – the UK continues to stand by the people of Sierra Leone.
“We have pre-positioned vital aid supplies and helped prepare the country’s response to disasters. We are already working with the Government of Sierra Leone to coordinate the rescue efforts and are ready to provide further assistance to those in need.”
Foreign Secretary Boris Johnson added: “I am deeply saddened by the tragic loss of life. My thoughts and prayers are with all those affected at this horrific time. We are working with the Government of Sierra Leone to provide support where necessary.”
The EU Commissioner for International Cooperation and Development, Neven Mimica, tweeted that the “#EU stands by the victims and is ready to help”.
Survivors and volunteers continued to search through the mud for their relatives, many of whom were feared to have been buried as they slept.
The Sierra Leone National Broadcasting Corporation showed images of people bringing bodies to the morgue in rice sacks.
Abdul Nasir, programme co-ordinator for the International Federation of Red Cross and Red Crescent Societies, said: “In places, entire communities seem to have been washed away and whatever is left is covered in mud.”