The FBI has said there was no wiretap of Trump, or Trump Tower.  But, if you wanted to hear Trump's discussions with others in his inner circle just come up with a reason to do "surveillance" on some of his members.  Same as a tap on Trump. Flynn was obviously a target, as info from his "surveillance" was printed in the New York Times.
These guys in the intelligence community use words to deflect on purpose. They don't say that "neither Trump or anyone associated with him, or anyone in his campaign was tapped or under surveillance". That would obviously be a lie.  There are so many ways for the FBI, NSA, Homeland Security, etc. to conduct "surveillance" on people and listen in on conversations, monitor internet communications, bug restaurants frequented, etc. 
The information from these was handed off not only to the newspapers, but to Hillary, and Obama for sure.