It has come to light that Obama, who has been recognised for giving greater role to multilateral diplomacy unlike the previous Bush administration, has approved a huge increase in the number of US special forces carrying out search-and-destroy missions against radical groups, particularly Al Qaeda.
American troops are now operating in 75 countries compared with about 60 at the beginning of last year, the Washington Post reported on Sunday.
In the past 18 months he has ordered a big expansion in Yemen and the Horn of Africa known areas of strong Qaeda activity and elsewhere in the Middle East, central Asia and Africa.
Obama has asked for a 5.7 percent increase in the Special Operations budget for fiscal 2011, for a total of $ 6.3 billion, plus an additional $ 3.5 billion in 2010 contingency funding, the report said.
It said Obama has also approved pre-emptive special forces strikes to disrupt terror plots, and has given the units powers and authority that was not granted by George Bush when he occupied the White House.
Commanders are now planning greater use of these special forces for preemptive or retaliatory strikes around the globe when a plot has been identified, or after an attack linked to a specific group.
Former Bush officials, still smarting from accusations that their administration overextended the president's authority to conduct lethal activities around the world at will, have asked similar questions.
"While they seem to be expanding their operations both in terms of extraterritoriality and aggressiveness, they are contracting the legal authority upon which those expanding actions are based," John B Bellinger III, a senior legal adviser in both of Bush's administrations, was quoted as saying by the daily.
The surge in Special Operations deployments, along with intensified CIA drone attacks in western Pakistan, is the other side of the national security doctrine of global engagement and domestic values President Obama released last week.
Of about 13,000 US special forces deployed overseas, about 9,000 are evenly divided between Afghanistan and Pakistan.
The United States "will not merely respond after the fact" of a terrorist attack but will "take the fight to Al Qaeda and its extremist affiliates whether they plot and train in Afghanistan, Pakistan, Yemen, Somalia and beyond," John O Brennan, the White House counterterrorism director, said last week.
"Eighty percent of our investment is now in resolving current conflicts, not in building capabilities with partners to avoid future ones," another official said.
A key advantage of using "secret" forces is that their operations are rarely discussed in public.
A top UN human rights official has questioned the jurisdiction under international law to conduct such raids, particularly when they kill innocent civilians.
In a report to the UN Human Rights Council, Philip Alston, the special rapporteur on extrajudicial executions, warned that the "prolific" use of targeted killings, mainly by unmanned US aircraft, was setting a damaging example that other countries would follow.
However, the US State Department has argued that targeted killings abroad are legally justified, citing the principle of self-defence under international law.
Defence Secretary Robert Gates insisted US lawmakers are kept fully informed about CIA operations abroad, including widely reported drone bombing raids on militants in Pakistan.
"I have no doubt whatsoever that the intelligence committees in the United States Congress are fully informed of the activities the CIA is carrying out," said Gates, a former director of the spy agency, at the Shangri-La security conference in Singapore on Saturday.
Image: US President Barack Obama
Osama hiding in Pakistan: CIA chief
UP-born Pak national funding Al Qaeda, Taliban: US
The book that Barack Obama enjoyed reading
Bangalore blasts a terror drill by Al Qaeda?
Barack Obama awaits his Nobel prize money