Google has reportedly been tightening its approach to Android modification by OEMs, inserting new “non-fragmentation clauses” into contracts and even attempting to delay devices which replace its own search with that of Bing. According to BusinessWeek‘s exec sources at LG, Toshiba, Samsung, Facebook and others, Google is now insisting that all modifications be signed off by Andy Rubin, with the threat of delayed access to future code hanging over their heads.

The sources suggest that OS modifications, new UIs, or even partnerships with other companies are all coming under Google’s microscope, especially if they concern search or navigation. Rubin claims the standard Android agreement with manufacturers has always contained such clauses, and John Lagerling, director of global Android partnerships at Google, says it’s a matter of quality control and working toward a “common denominator”; however, the reports suggest the policies have recently been tightened.

As a result, several companies have supposedly complained to the US Department of Justice. This week, Microsoft announced it will be requesting the European Union begin an antitrust investigation into Google over allegations it is acting in a way that unfairly prevents competition. More information on that here.