Washington, May 2 (IANS) The US expects retaliation from Al Qaeda in the aftermath of the death of its chief Osama bin Laden, an official of the Department of Homeland Security told CNN.

‘We certainly anticipate threats of retaliation. This is an organisation that declared war on the United States more than a decade ago. Threats from Al Qaeda are not a new phenomenon,’ the unnamed official said.

The US has put its diplomatic facilities around the world on high alert and issued a global travel warning for American nationals, shortly after President Barack Obama announced that Osama had been killed in Pakistan.

‘Given the uncertainty and volatility of the current situation, US citizens in areas where recent events could cause anti-American violence are strongly urged to limit their travel outside of their homes and hotels and avoid mass gatherings and demonstrations,’ the State Department said in a worldwide travel warning.

‘We remain at a heightened state of vigilance and our security posture, which always includes a number of measures both seen and unseen, will continue to protect the American people from an evolving threat picture both in the next days and beyond,’ the Homeland Security official said.

Some vague threats were reportedly posted on a forum titled Shumukh al-Islam, the exclusive outlet for official messages from Al Qaeda, according to the SITE Intelligence Group that monitors online jihadist activities.

‘America will reap the same if the news is true and false,’ said one post on the website, while another said: ‘The lions will remain lions and will continue moving in the footsteps of Osama.’