Satellite image of Typhoon Usagi
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Typhoon Usagi headed for Philippines and Taiwan

21 September 2013 Last updated at 01:48 BST

The Philippines and Taiwan are braced for Typhoon Usagi, which meteorologists say could become the most powerful typhoon of 2013.

Pagasa, the Philippine government's weather agency, said the typhoon had wind speeds of up to 175 km/h (110 mph) and gained strength early on Friday.

Both Taiwan and the Philippines have issued alerts and warned boats to exercise caution.

Tim Allman reports.