Josef Ackermann, the former Deutsche Bank boss, resigned on Thursday as chairman of Zurich Insurance over the apparent suicide of the Swiss insurer's chief financial officer.

The blaze has charred nearly 187,500 acres - an area larger than the land mass of Chicago - since it erupted on Aug. 17.

The United States could improve how it spots and prevents risks in the financial system from turning into destabilising crises, a global regulatory task force said.

A colossal wildfire raging across the western edge of Yosemite National Park swept further into the park on Sunday and forced the evacuation of some its camps. The fire was also threatening power and water supplies to San Francisco, about 200 miles to the west.

U.S. wildfire managers facing increasingly strained resources have opened talks with Pentagon commanders and Canadian officials about possible reinforcements of personnel and aircraft to battle dozens of blazes.

Canada should force railways to take out enough insurance to cover damages caused by major incidents, the Canadian Senate says in a report issued after last month's deadly train disaster in Quebec.

A wildfire that has forced the evacuation of more than 2,000 homes in central Idaho roared largely unchecked into a 12th day on Monday near the ski resort of Sun Valley.

The government of the Canadian province of Quebec has added Canadian Pacific Railway to the list of companies it says should help pay clean-up costs after an oil tanker train disaster in July.