WordNet
reconnaissance in force
n. an offensive operation designed to discover or test the enemy's strength (or to obtain other information)
Usage examples of "reconnaissance in force".
The very next day he led a reconnaissance in force all the way to the Canal, disobeying direct orders at the risk of being relieved or even court-martialled.
For your private information, I'm putting together a reconnaissance in force for Adler.
It looked like there was no way around it: reconnaissance in force was called for by the manual.