Petition to US government was sent by part of Polish government to debunk current raports and call out for International Comittee to start investigation. This petition once it will reach 25.000 supporters/signatures will be considered officially as start point of research.
Link: https://petitions.whitehouse.gov/petition/support-polish-nation-appeal-international-investigation-smolensk-2010-air-crash/tDSMBfXr