Russian President Vladimir Putin has no plans on limiting his military’s presence along the Ukraine border, despite international condemnation following the downing of a Malaysia Airlines passenger jet last week, U.S. officials told TheBlaze.

U.S. and European officials are closely monitoring Russia’s movements in Ukraine and are going increasingly concerned about the Kremlin’s presence, which they say has increased both its intelligence and military capabilities in the region. The situation is both fragile and fluid as investigators continue to rummage through the debris and remove the bodies of the 298 passengers killed on Malaysian Airlines Flight 17.

“The crisis in Ukraine shows no signs of abating,” one U.S. official with direct knowledge of the region told TheBlaze. “In recent weeks, the Russian military has bolstered its presence along the Ukrainian border. Moreover, Russian support to the separatists – which includes tanks, artillery, and air defense systems – has also increased.”

Pro-Russian militants take the military oath of allegiance to the so-called People's Republik of Donetsk during the ceremony in the eastern Ukrainian city of Donetsk on June 21, 2014. Russian President Vladimir Putin has ordered troops in central Russia on 'full combat alert,' the defence minister said on Saturday, a day after the Kremlin confirmed it was beefing up its military presence at the border with Ukraine. AFP PHOTO/ ALEXANDER KHUDOTEPLY ALEXANDER KHUDOTEPLY/AFP/Getty Images

Pro-Russian militants take the military oath of allegiance to the so-called People’s Republik of Donetsk during a ceremony in the eastern Ukrainian city of Donetsk, June 21, 2014. (ALEXANDER KHUDOTEPLY/AFP/Getty Images)

A man walks amongst the debris at the crash site of a passenger plane near the village of Grabovo, Ukraine, Thursday, July 17, 2014. Ukraine said a passenger plane carrying 295 people was shot down Thursday as it flew over the country, and both the government and the pro-Russia separatists fighting in the region denied any responsibility for downing the plane. (AP Photo/Dmitry Lovetsky)

A man walks amongst the debris at the crash site of a passenger plane near the village of Grabovo, Ukraine, Thursday, July 17, 2014. (AP Photo/Dmitry Lovetsky)

Putin has denied all allegations that Russia was involved in the shoot-down of the passenger jet; Russian Army Lt. Gen. Andrei Kartapolov suggested to the BBC last week that it could have been a Ukrainian jet fighter that took the plane down.

U.S. officials said Tuesday that the intelligence so far indicates that the Malaysia flight was shot down by rebels, and that there was no direct official link to Russia.

Niles Gardiner, an expert on transatlantic relations and director of the conservative Heritage Foundation’s Margaret Thatcher Center for Freedom, told TheBlaze there is very little doubt among experts familiar with Russian military operations that “the Russians are supplying all the weapons themselves” to separatists in eastern Ukraine.

Gardinar said Russian special forces and intelligence agents have been infiltrating various parts of Ukraine’s eastern cities and instigating the majority of the conflicts that have led to the escalating crisis.

“This is a proxy war being fought by Moscow,” Gardiner said. ”Some of the operatives are Russian special forces and it’s no surprise that the Russians are going to deny responsibility of the downing of the Malaysian airliner. They believe they can operate with impunity and do anything they like. Obama is out on vacation and the Europeans don’t have any backbone. Clearly, with Obama it’s just open season.”

President Barack Obama told reporters this week that “the burden now is on Russia” to stop rebels who are tampering with evidence at the crash site.

Putin has “direct responsibility to compel them to cooperate with the investigation,” Obama said.

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