Colonel Prudencio Asto, speaking for the 6th Infantry Division, said an improvised explosive device fashioned from a 60-millimeter mortar with a mobile phone as trigger was planted beside the highway in Datu Saudi Ampatuan town, where an Army medical and dental team was to pass on its way to Barangay Kitapok.
He said civilians became suspicious of a plastic bag abandoned by the roadside and informed authorities about it.
Asto said army and police bomb experts safely defused the bomb.
The discovery came a day after an improvised bomb went off in front of the Land Bank of the Philippines branch in Tacurong City but it was not clear f the two incidents were related, he said, adding that the BIFF was the main suspect in the foiled bombing.
The BIFF, a group that broke away from the Moro Islamic Liberation Front, has been staging attacks on government positions in Maguindanao.
In August and September, hundreds of families fled their homes because of clashes involving the BIFF.