My browser automatically downloading!!

I have a macbook pro, for a while now sometimes when im on safari i new window will automatically open (blank) then a download would start in the top right corner. In a split second its downloaded something, example below, will try get pic up if i can.
Mackeeper-6.2.5.pkg
380 kb

Mackeeper-5.2.5.pkg
380 kb

and so on. What is this? Is it a virus?

G'day and welcome to nthe forums.

Well some describe MacKeeper as severe malware so you are not too far off the mark. Make sure it is not in your Applications or Utilities folders. Make sure you have blocked pop ups in Safari Preferences and download Adblock for Safari as an extra measure.