Azerbaijan’s leader on Monday accused Moscow of carrying out a “cover up” over a passenger jet crash last month that claimed 38 lives, as relations sour between the two neighbors.

The Brazilian Air Force Laboratory has sent data from the flight recorders of an Azerbaijan Airlines plane to Kazakh investigators. The plane crashed on December 25 near the city of Aktau, Radio Liberty reports.

Brazilian investigators have reportedly begun analyzing black boxes of the Azerbaijan Airlines Embraer E190 involved in the crash. The news comes almost two weeks after the regional aircraft operating flight J28243 from Baku to Grozny crash-landed near the city of Aktau in Kazakhstan, killing 38 people.

Azerbaijan Airlines flight J2-8243 from Baku ... crash would become known after the data from flight recorders sent to Brazil is accessed.

Black boxes from plane crash will be delivered to Aeronautical Accidents Investigation and Prevention Center (CENIPA) in Brazil, says Kazakh Transport Ministry - Anadolu Ajansı

In the crash’s aftermath, Azerbaijan has unleashed rare and stinging criticism of Russia, with the country’s president saying Moscow’s response has caused “surprise, regret and rightful indignation.”

The voice recorders from the Brazilian-made plane were analyzed in Brasilia before the data was handed to Kazakh authorities. Meanwhile, Azerbaijan has directed unusually strong words towards Moscow.

Indonesia on Monday officially joined the BRICS bloc of developing nations, marking a significant expansion of the group's global influence.

Kazakhstan finds itself caught between Russia and Azerbaijan as it investigates a jet crash that has ignited tensions between its two neighbors.

Photos provided by Azerbaijani media outlet AnewZ show that the Azerbaijan Airlines plane which crashed near Aktau in Kazakhstan has signs of damage consistent with an attack from outside the aircraft.

Brazil Assisting Kazakhstan In Probe Of Downed Azerbaijan Airlines E190 is published in Aerospace Daily & Defense Report, an Aviation Week Intelligence Network (AWIN) Market Briefing and is included with your AWIN membership.