Philippine President Benigno Aquino has declared a state of national calamity amid the large-scale devastation caused by Typhoon Haiyan.

In a statement, he said the two worst affected provinces, Leyte and Samar, had suffered massive destruction and loss of life.

A huge international relief effort is under way, but rescue workers have struggled to reach areas cut off since the storm.

At least 10,000 people are feared to have been killed, and thousands of survivors desperately require aid.

The US has deployed an aircraft carrier and navy ships to the Philippines, while the UK is sending a naval destroyer.

UN Secretary General Ban Ki-moon described images of the impact of the storm as "heartbreaking".

The UN would launch a large-scale humanitarian plan, and allocate m (?15.5m) "to fund critical relief efforts", he said.

"Many thousands of people are reported to have died and almost 10 million people have been affected... Let us all show our solidarity with the people of the Philippines at this time of need," he added.