(CNN)A missile that brought down Malaysia Airlines Flight 17 in eastern Ukraine in 2014 was fired from a launcher belonging to Russia's 53rd anti-aircraft missile brigade, investigators said Thursday.
Missile that downed MH17 'owned by Russian brigade'
The announcement is the first time the investigative team has identified a specific division of the Russian military as possibly being involved in the strike. Russia has repeatedly denied involvement in the incident.
The Buk missile was fired from a farm near Pervomaisk, the Joint Investigation Team into the MH17 disaster told a news conference in the Netherlands.
An update posted online by investigators Thursday said the JIT was "convinced" that the Buk TELAR (transporter erector launcher and radar) used to down MH17 originated from the 53rd anti-aircraft missile brigade, a unit of the Russian army from Kursk in Russia.
The team's conclusion was based on "extensive comparative research" that identified characteristics particular to that individual Buk launcher.
"At the time this area was under control of pro-Russian separatists," said Fred Westerbeke, chief prosecutor of the National Prosecutor's Office of the Netherlands. The Buk launcher of the 9M38 series "was transported from the territory of the Russian Federation and was returned to that territory of the Russian Federation afterwards."
Westerbeke highlighted how "this raises questions such as to whether the brigade was actively involved in downing MH17. It is an important question which the JIT are still investigating."
A total of 298 people from 17 countries died when the flight from Amsterdam to Kuala Lumpur, Malaysia, was brought down in eastern Ukraine in July 2014.
The team has also called for witnesses and members of the public to come forward to help identify anyone involved in operating the missile system.
"The authorities of the Russian Federation have, up to now, not reported to the JIT that a Buk of the 53rd brigade was deployed in Eastern Ukraine and that this Buk downed flight MH17," Westerbeke said.
"On 15 October 2014 the JIT already asked the Russian authorities to provide the JIT (in line with resolution 2166 of the UN Security Council) with all information that may be important for establishing the truth.
"Because the JIT no longer wants to exclusively turn to the Russian authorities to obtain information about this subject, the JIT also calls in the assistance from the public today -- through the media -- to answer questions that relate to the control of and the use of the Buk TELAR, as well as about the missile that was launched with that TELAR."
Russia rejected the accusations leveled at it by the investigation in a Defense Ministry statement carried by state media.
"The Russian Defense Ministry, both in the first hours after the tragedy, and further officially denied the insinuations of the Ukrainian side about the alleged involvement of Russian servicemen to the catastrophe that happened in the skies of Ukraine and brought the relevant evidence to the Dutch investigation team," the statement said.
"Not a single anti-aircraft missile system from Russia has ever crossed the Russian-Ukrainian border."
Families of the victims penned an open letter to "the Russian people" earlier this month, describing their ongoing grief and heartache over the incident and urging Moscow to bring those responsible to justice.
"We appeal again for the Russian government to cooperate fully with the international investigation into MH17," the letter in Russian newspaper Novaya Gazeta read.
"It will not bring our families back but the truth does matter, the truth does exist and we want those responsible for MH17 to be identified and held accountable."
The letter also accused Russian media of leading a "vile and deceitful campaign" over the incident through the broadcasting of "misinformation intended to distract and confuse, to create an alternative reality."