What is the source of the war in Ukraine, and what is Putin's ultimate goal?

Multiple reports of explosions, bombings, and Russian military vehicles entering Ukraine from various points along the Russian border have surfaced overnight, with a mounting number of deaths on both sides.

For months, if not years, many of the president's closest supporters have been anticipating the invasion of Ukraine.

Putin drew global attention earlier this week when he sent troops into two pro-Russian breakaway regions in eastern Ukraine and declared their independent states.

Putin's declaration that Russian forces dispatched into the region will operate as "peacekeepers" has been dismissed by Western officials and analysts, who believe the current step could be a prelude to a broader invasion of Ukraine.

Given the ongoing fighting in the Donbas between separatists backed by Russia and Ukrainian military, political commentators have predicted that Russia could make such a move for some time.

Nonetheless, Putin's moves today, with a larger-scale onslaught, come sooner and look to be more broad-based than many had anticipated.

On Thursday morning, the Kremlin made new statements, saying Putin would decide how long the military operation would last "depending on its accomplishments and goals." According to Reuters, Putin's spokesperson Dmitry Peskov also told reporters that Ukraine must be "liberated," but that "nobody is talking about the occupation of Ukraine."

What is happening in Ukraine and why is it important:

For some time, there have been rising worries of a military battle between Russia and Ukraine, and eastern Ukraine has been the site of a proxy war between the two countries.

Pro-Russian separatists declared the Donetsk People's Republic and the Luhansk People's Republic in the eastern portion of Ukraine shortly after Russia annexed Crimea from Ukraine in 2014, much to the chagrin of the Ukrainian authorities.

Since then, there have been intermittent clashes and fighting in the Donbas region between Ukrainian army and separatists.

The "Minsk agreements" were a series of attempts by Germany and France to negotiate peace between Russia and Ukraine. Although there have been times of cease-fire in the Donbas, both Ukraine and Russia have accused each other of breaking the terms of the agreements, and combat has resumed.

The military struggle in the Donbas, which is commonly referred to as "war," has already claimed the lives of 13,000 to 14,000 people. Given the civil war-like character of the fight, a reliable estimate of the death toll is difficult to come by.

Putin told reporters on Tuesday that "the Minsk agreements were dead long before yesterday's [Monday's] recognition of the people's republics," blaming Kyiv once again for their failure.

What is Putin's goal?

Essentially, the conflict over Ukraine is a contest for power and influence. In recent years, Ukraine's administration, now led by President Volodymyr Zelenskyy, has shifted its focus to the West, aiming to join the EU and NATO and move away from Russia's post-Soviet orbit.

Meanwhile, Putin has described the dissolution of the Soviet Union as a catastrophe, and has worked to rebuild Russia's power base and sphere of influence over former Soviet states such as Belarus, Georgia, and Ukraine — the USSR's crown jewel and natural buffer against Europe — during his 22-year rule.

Putin has frequently praised Russia and Ukraine's historical unity, and he did so again on Monday when he ordered soldiers into the Donbas.

Ukraine's move toward the West irritates Moscow because it does not want NATO or the EU to expand eastward to include Ukraine, despite the fact that Ukraine has no immediate plans to join either organization.

Russia wanted legal guarantees that Ukraine will never be accepted to NATO in December, but these demands were turned down. According to analysts, Putin knew the demands would be rejected, but was able to claim that Russia's security concerns had been overlooked, which he was able to sell to the Russian public through the media, the majority of which is pro-Putin because it is either state controlled or has ties to the government.

As a result, it's no surprise that Russian official media has frequently blamed Ukraine and the West for the escalation of tensions in the Donbas region, accusing both of propagating false information and neglecting Russia's security demands.

The United States, the European Union, Japan, Australia, and the United Kingdom have all announced new sanctions against Russia, despite the fact that the country has previously been sanctioned for its invasion of Crimea, 2016 US election meddling, cyberattacks, and other crimes.