The paper said it had spoken to more than six officials, “including current and former military and intelligence officials” as well as senior policy makers in the Bush administration.
They said that the order, signed by Mr Rumsfeld with the approval of President George W Bush, was intended to make it easier for the US military to act outside officially declared war zones at short notice.
In total, 15 to 20 countries were covered by the mandate and attacks had been carried out in Pakistan, Syria and “several other countries,” the paper reported.
Some were conducted in coordination with the CIA and one was broadcast live to CIA headquarters in Virginia, via cameras mounted on aircraft.
The paper’s sources also claimed that “as many as a dozen” attacks had been called off – “often to the dismay of military commanders” – due to lack of evidence or because they were considered too dangerous or “diplomatically explosive”.
The US has carried out many attacks along Pakistan‘s border areas recently and was blamed for an attack in eastern Syria last month.