Terror groups and the exploitation of turmoil

The assassination of Osama bin Laden in May last year was seen as a significant blow to al Qaeda, the murderous organisation he founded and funded for many years.

His deputy Ayman al-Zawahiri, while sharing the same extreme views, is not regarded as charismatic or as effective as bin Laden at managing the organisation.

This gave hope that al Qaeda would decline as a global threat and perhaps cease to exist.

However, the organisation has proven to be resilient and opportunistic in the extreme.

Offshoots have formed and links have developed with other radical Islamist groups dedicated to advancing their interests through violence.

For example, the areas of relative lawlessness in the vast tribal regions of Yemen were fertile grounds for the establishment of 'al Qaeda in the Arabian Peninsula' (AQAP).

This group has made several attempts to attack aircraft in recent years and while it has so far failed to detonate a bomb inside a plane it remains a serious threat to airline safety around the world.

AQAP had sought to increase its presence and influence within Yemen in the midst of the upheaval that led to the resignation of long-time dictator Ali Abdullah Saleh.

As the nation has stabilised over recent months, AQAP has come under increasing pressure, from within and beyond Yemen.

Drone attacks by the United States have had a major impact on AQAP leadership while ground assaults by Yemeni military forces have reduced its range of operations within that country.

The al Qaeda linked group 'al Shabaab' which had taken control of large swathes of Somalia has also suffered serious setbacks in recent weeks.

There are reports of United States drones targeting the al Shabaab leadership. Soldiers from several African nations including Kenya are also driving the group out of the capital Mogadishu and cutting off its supply lines.