MANILA, Philippines – The United States said relief channels were opening up on Thursday (November 14th) in the typhoon-ravaged Philippines, as the UN admitted that it had not acted quickly enough to help survivors, AFP reported.

The aircraft carrier USS George Washington arrived in the Philippines Thursday, one of eight American ships in the region supporting the aid effort. Washington committed $20m to the effort, six days after Super Typhoon Haiyan struck.

Britain will send the helicopter carrier HMS Illustrious – the largest ship in its navy – Prime Minister David Cameron said Thursday. He said Britain's total aid was now in excess of 20m pounds ($32m)

But UN Humanitarian Chief Valerie Amos said the scale of the disaster and logistical challenges meant that some places remained without help six days on from the storm.

"I do feel that we have let people down," she told reporters.

After criticism of China's initial offer of $100,000, the Chinese embassy in the Philippines said that Beijing would provide an additional $1.6m in the form of blankets, tents and other materials.

US officials said the aid operation was slowly getting into gear after daunting challenges posed by shattered ports, roads and communications infrastructure.

The US is doubling the number of MV-22 Ospreys to eight, joining a team of Marines equipped with amphibious vehicles and 12 cargo planes delivering food, water and other essentials.

Malaysia is sending aid flights and military medics, while Indonesian planes deliver supplies including water filters. Thailand is donating some $2.7m in aid and an unspecified number of C-130s to take in medical supplies.

Survivors in Tacloban and the central Philippines are pleading for basic needs and for security to protect them from mobs pilfering what little aid now gets through.