The U.S. military has considered air strikes against targets in a suspected terrorist safe haven in the desert wastelands of West Africa.
The border area between Algeria and Mali is remote and official comment on anti-terrorist activities there is rare.
But VOA has learned U.S. involvement in a crackdown on al-Qaida linked armed groups in the desert region has taken on new dimensions, in part out of concern terrorist leaders forced from other countries may have sought refuge there.
Defense officials say the United States has been sharing intelligence with Algeria and has deployed counter-insurgency specialists in Mali.
One of the officials, speaking on condition of anonymity, says there was a recent instance when American personnel in Mali called for a U.S. air strike against a suspected terrorist facility.
It is not clear whether the proposed target was a suspected training camp or possibly a terrorist arms convoy.
But the official says the proposed bombing mission was scrapped because the target could not be confirmed. The military official says commanders did not want to risk innocent civilian casualties.
Another defense official says such bombing missions remain an active option.
The previously-undisclosed cooperation has already begun to show results. A combined operation last month saw Malian troops force a suspected terrorist weapons convoy loaded with arms, ammunition, and communications gear across the border into Algeria, where Algerian forces successfully intercepted it.
Pentagon officials would not discuss the extent of U.S. involvement in that mission.
Until now, it appeared the only U.S. assistance in the region was counter-terrorist training for select West Africa countries, including Mali.
A senior Malian defense official last week confirmed the presence of trainers in his country. But the official said no American troops were in the field engaged in actual anti-terrorist operations.
However, defense officials have confirmed the U.S. troops in Mali are elite Special Operations forces. They say these soldiers could be tasked with actual field missions on an as-needed basis.
Mali is among the African countries which have offered the Pentagon access to airfields and other facilities for use as possible temporary military operating locations.
A key regional terrorist group U.S. officials are concerned about is the Salafist Group for Preaching and Combat. The group is suspected of involvement in the kidnapping last year of European tourists traveling in the Sahara Desert.
A warning issued in December by the State Department advised against travel to Mali's northern regions. The warning said the area has become what was termed "a safe haven" for the Salafist Group.