would like to suppress the output of pkill on a background process

I have a shell-script in which I do an iostat -c 1 > data.cpu. & Later in the script, after I've collected the data I'm interested in, I do a pkill iostat which kills iostat and allows me to continue by processing data.cpu and generating a report written to stdout. Part of the report includes + Terminated iostat -c 1 > data.cpu produced by the pkill. For aesthetic reasons I would like to prevent the "Terminated" message from appearing. I tried various redirects, but so far I haven't succeeded. Is there any way to prevent this part of the output?