Australian and Dutch experts examine the area of the Malaysia Airlines Flight 17 plane crash on Sunday, August 3, near the village of Rossipne, in the Donetsk region of eastern Ukraine. The United States says a surface-to-air missile took down the Boeing 777 on Thursday, July 17, as it was flying over Ukraine from Amsterdam, Netherlands, to Kuala Lumpur, Malaysia, killing all 298 people aboard. Ukrainian officials have accused pro-Russian rebels of downing the jet, but Russia blames Ukraine’s recent military operations against the rebels.

A convoy of international forensic experts and members of the mission for the Organization for Security and Co-operation in Europe travel across a damaged bridge near Debaltsevo village on August 3 after leaing the area of the crash.

Police secure a refrigerated train loaded with bodies of passengers from Malaysia Airlines Flight 17 as it arrives in a Kharkiv, Ukraine, factory on Tuesday, July 22.

A pro-Russia rebel passes wreckage from the crashed jet near the eastern Ukraine village of Hrabove on Monday, July 21.

Wreckage from the jet lies in grass near Hrabove on July 21.

A man covers his face with a rag as members of the Organization for Security and Co-operation in Europe and the Dutch National Forensic Investigations Team inspect bodies in a refrigerated train near the crash site in eastern Ukraine on July 21. The remains of 16 people are still missing, Ukrainian President Petro Poroshenko said.

Emergency workers carry a victim’s body in a bag at the crash site on July 21. Search teams have recovered more than 270 bodies, officials say.

A piece of the Boeing 777 lies in the grass in eastern Ukraine’s Donetsk region on July 21.

An armed pro-Russia rebel stands guard next to a refrigerated train loaded with bodies in Torez, Ukraine, on Sunday, July 20.

Ukrainian State Emergency Service employees sort through debris on July 20 as they work to locate the deceased.

A woman covers her mouth with a piece of fabric July 20 to ward off smells from railway cars that reportedly contain passengers’ bodies.

Toys and flowers sit on the charred fuselage of the jet as a memorial on July 20.

People search a wheat field for remains in the area of the crash site on July 20.

A woman walks among charred debris at the crash site on Sunday, July 20.

Emergency workers load the body of a victim onto a truck at the crash site on Saturday, July 19.

Emergency workers carry the body of a victim at the crash site of Malaysia Airlines Flight 17 in eastern Ukraine on Saturday, July 19.

A large piece of the main cabin is under guard at the crash site on July 19.

Victims’ bodies are placed by the side of the road on July 19 as recovery efforts continue at the crash site. International officials lament the lack of a secured perimeter.

A man looks through the debris at the crash site on July 19.

An envelope bearing the Malaysia Airlines logo at the crash site on July 19.

Armed rebels walk past large pieces of the Boeing 777 on July 19.

Ukrainian rescue workers walk through a wheat field with a stretcher as they collect the bodies of victims on July 19.

A woman looks at wreckage at the Malaysia Airlines Flight 17 crash site on July 19.

Pro-Russian fighters stand guard as the Organization for Security and Co-operation in Europe delegation arrives at the crash site of Malaysia Airlines Flight 17 in eastern Ukraine on Friday, July 18.

A woman walks through the debris field on July 18.

Pro-Russia rebels stand guard at the crash site.

Wreckage from Flight 17 lies in a field in Shaktarsk, Urkaine on July 18. International inspectors are headed to the crash site to search for the plane’s flight data recorders.

A man covers a body with a plastic sheet near the crash site July 18. The passengers and crew hailed from all over the world, including Australia, Indonesia, Malaysia, Germany and Canada.

A diver searches for the jet’s flight data recorders on July 18.

Coal miners search the crash site.

Wreckage from the Boeing 777 lies on the ground July 18 in rebel-held eastern Ukraine.

People search for bodies of passengers on July 18.

A woman walks past a body covered with a plastic sheet near the crash site July 18. The diversity of the victims’ nationalities has turned the crash into a global tragedy.

Belongings of passengers lie in the grass on July 18.

People inspect the crash site on Thursday, July 17.

People walk amid the debris at the site of the crash.

Debris smoulders in a field near the Russian border.

Fire engines arrive at the crash site.

A man stands next to wreckage.

Debris from the crashed jet lies in a field in Ukraine.

Family members of those aboard Flight 17 leave Schiphol Airport near Amsterdam, Netherlands.

A large piece of the plane lies on the ground.

Luggage from the flight sits in a field at the crash site.

A couple walks to the location at Schiphol Airport near Amsterdam where more information will be given regarding the flight.

Flight arrivals are listed at the Kuala Lumpur International Airport in Sepang, Malaysia.

Debris from the Boeing 777, pictured on July 17.

A man inspects debris from the plane.

Wreckage from the plane is seen on July 17.

A man talks with security at Schiphol airport in Amsterdam, Netherlands, on July 17.

Wreckage burns in Ukraine.

A man stands next to the wreckage of the airliner that crashed July 17 in Ukraine.

People inspect a piece of wreckage believed to be from Malaysia Airlines Flight 17 in Ukraine. This image was posted to Twitter.

People inspect a piece of wreckage believed to be from Malaysia Airlines Flight 17. This image was posted to Twitter.

A piece of wreckage believed to be from Malaysia Airlines Flight 17. This image was posted to Twitter.

A piece of wreckage believed to be from MH17. This image was posted to Twitter.

An airsickness bag believed to be from MH17. This image was posted to Twitter.

A piece of wreckage believed to be from MH17. This image was posted to Twitter.

 Donetsk, Ukraine (CNN) — A new buildup of Russian troops along the Ukraine border raised concerns Tuesday that Moscow might be contemplating another intervention like the one that annexed Crimea earlier this year.

According to a NATO official, Russia now has about 20,000 troops stationed “in an area along the entire border with eastern Ukraine.” The buildup nearly doubled the troop deployment in the last week by adding 8,000 more forces to 12,000 already there, the official said.

It comes a week after the United States and the European Union increased economic sanctions on Russia for supporting pro-Russian separatists fighting Ukraine government forces in the eastern regions of Donetsk and Luhansk, along the border with Russia.

In addition, Russia’s Defense Ministry is staging a week of military exercises involving air troops and anti-missile defense forces. The exercises are taking place in Russia’s southern Astrakhan region, roughly 500 miles from the border with Ukraine.

Similar military exercises in the region preceded Russia’s annexation of Crimea in March, which escalated the Ukraine conflict following the ouster of pro-Moscow Prime Minister Viktor Yanukovych a month earlier.

Donetsk braces for offensive

Meanwhile, Ukraine government security officials said Monday they were preparing for a “massive assault” on Donetsk city, state media reported. Inside the city, a rebel stronghold for months, shelling has already pushed some residents underground into cellars and half-built basements. Read More.