Image copyright EPA Image caption The Russian military is using the drills to train soldiers to protect Europe’s border
Russia has staged military drills with Belarus in the Baltic Sea, while Hungary said its troops could be deployed to Poland to help halt migrants at the EU border.
According to reports in Belarus, hundreds of tanks and armoured vehicles were used for the exercises, which took place on Sunday.
Russia and Belarus have a shared border.
Russian President Vladimir Putin is in the region ahead of his summit with US President Donald Trump later this week.
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According to the Belarusian agency BelTA, hundreds of Russian paratroopers from the 29th Guards Airborne Regiment also arrived in Belarus with seven military aircraft, as well as military advisers and weapons.
Russian Deputy Defence Minister Sergey Khomitsky said at a press conference in Minsk that the military manoeuvres were a response to “attacks” on Russia on the EU border in Latvia.
Russia had also threatened to deploy its brigades to Belarus in the near future, he said.
Mr Putin is in the Black Sea state for a summit with Mr Trump on Wednesday and Thursday.
In July, Moscow and Washington agreed a “strategic partnership” that aims to end “destructive rivalry” on world and security issues, including over Afghanistan and North Korea.
Another joint military exercise, involving Russia and Belarus, was conducted in Belarus last year.
Russia has denied targeting civilians in Syria with its air strikes , but this has not stopped the international community criticising its actions.
The Kremlin says its military operation in Syria is conducted solely for its own security, and that it will stop if the long-standing deal it has struck with Syrian President Bashar al-Assad is broken.
The EU is now in the grip of a migrant crisis after thousands of people have reached European shores, and some 2,400 have died trying so.
According to the BBC’s eastern Europe correspondent Aleksandar Vasovic, Hungary is considering deploying troops to Poland’s southern border with the EU.
Mr Khomitsky said the Hungarians were ready to deploy about 200 troops to the Gamsanyi region, as well as a military hospital, but the ministry of defence told the Hungarian foreign ministry not to confirm this.
Hungary and Poland are at loggerheads over migration as well as over the issue of whether to let in refugees.
When Mr Trump appeared at a state dinner in Budapest earlier this month, he criticised the EU for its immigration policies, calling them a “disaster”.
He said: “I don’t see anything good coming out of those troubled countries right now. They want to take in a lot of people. You see what’s happening there. It’s a disaster. When they bring them in, you see what happens. The danger is tremendous.”
But Hungarian Prime Minister Viktor Orban said he was “very pleased” with the US leader’s recent visit, and praised his stance on migration.