Kate Winslet thought she knew her way around water after spending hours in chilly water shooting scenes for the Oscar-winning film Titanic.

The Pentagon is stepping up the hunt for al-Qaida fighters in Yemen, the ancestral home of Osama bin Laden, which remains a terrorist hornets’ nest despite efforts of US and Yemeni authorities over the past two years.

US and Afghan officials believe the assassination attempt against Afghan president Hamid Karzai was probably the work of fugitive members of the country’s ousted Taliban regime rather than al-Qaida terrorists, defence officials have said.