(CNN) United States President-elect Donald Trump will have a lot of global challenges to deal with, and Russia is one of them. Here's what you need to know.

Trump on Russia

"It is always a great honor to be so nicely complimented by a man so highly respected within his own country and beyond," Trump said about Russian President Vladimir Putin in a statement last December. "I have always felt that Russia and the United States should be able to work well with each other towards defeating terrorism and restoring world peace, not to mention trade and all of the other benefits derived from mutual respect."

One statistic that sums up the Russia issue

Putin has been increasing military spending for more than a decade as he modernizes Russia's creaking Soviet-era armed forces.

Billions of rubles have flowed into new generation battle tanks, strike aircraft and cruise missiles. Russian troops even have new uniforms replacing the outdated Soviet outfits.

One of the most controversial areas of Russian military spending has been nuclear weapons. Russia recently released a first image of its new heavy thermonuclear intercontinental ballistic missile, dubbed by NATO as the "Satan 2."

Moscow says the missile has a range of over 10 thousand kilometers, can strike the east and west coasts of the United States, and destroy countries the size of France with a single strike.

What should be Trump's top priority in the first 100 days?

The immediate concern is the conflict in Syria, where Russia is militarily backing Bashar al-Assad , the country's president. The US wants Assad gone and is supporting some anti-government rebels.

While past attempts to reach a deal between Washington and Moscow have failed, avoiding a direct confrontation between US and Russian forces - two nuclear superpowers - should be a priority.

Trump has repeatedly called for US and Russian forces to work together to destroy jihadist groups in Syria like ISIS, an approach that has been welcomed by the Kremlin.

Can Trump fix relations with Russia in the first term?

It's theoretically possible, but politically unlikely. The Kremlin wants a grand bargain that would see the US lift economic sanctions on Russia, recognize as legitimate its annexation of Crimea, and accept Moscow's interests in Ukraine and Syria.

Putin also wants NATO to roll back its post-Cold War expansion into Eastern Europe, and to abandon current missile defense plans

Progress on any of these issues may help to ease tensions between Russia and the US, but is likely to be painstakingly slow.

How big a priority is Russia for CNN readers?

Russia is the number three international priority (behind Syria and China), according to a very unscientific poll of CNN readers who took part in our interactive feature on the 10 biggest global challenges facing the next President.