According to Russian officials and the American academic Theodore Postol, the US decision to deploy its missile defense system in Europe was a violation of the treaty as they claim they could be quickly retrofitted with offensive capabilities; this accusation has in turn been rejected by US and NATO officials and analyst Jeffrey Lewis. Russian experts also stated that the US usage of target missiles and unmanned aerial vehicles, such as the MQ-9 Reaper and MQ-4 Triton, violated the INF Treaty which has also in turn been rejected by US officials.