Russian troops have moved into the eastern region of Ukraine that Russia has now recognized as "independent," according to the Prime Minister of NATO member Latvia and sources familiar with the latest US intelligence assessments, CNN reports.

“According to the information at my disposal, Putin is moving additional forces and tanks into the occupied Donbas territories,” Latvian Prime Minister Arturs Krišjānis Kariņš told CNN's Jim Sciutto on Wednesday. “By any definition that's a crossing of a sovereign territory into a neighboring country.”

Pressed specifically on whether he was referring to the entry of additional Russian troops since Moscow recognized the two separatist regions earlier this week, Kariņš replied: “Yes, according to the information at my disposal, this is exactly what we're seeing.”

Two other sources familiar with US intelligence confirmed to CNN that additional Russian troops have in fact crossed the border into the Donbas region since Russian President Vladimir Putin recognized the two regions and issued an order deploying “peacekeepers” into the Donbas on Tuesday. According to a senior US official familiar with the latest intelligence, Russia has deployed one to two so-called battalion tactical groups, Russia's main combat formation, each of which comprise an average of about 800 troops.

CNN has not independently verified the presence of additional Russian troops in the Donbas.

President Joe Biden on Tuesday described events now underway in Ukraine as “the beginning of a Russian invasion,” but senior administration officials have since declined to confirm whether additional Russian troops had entered into the Donbas — where unmarked Russian forces have propping up separatist fighters since 2014.

The US and European allies invoked sanctions against Moscow on Tuesday in response to Putin's moves, and the Biden administration is expected to announce Wednesday that it will allow sanctions to move forward on the company in charge of building the Nord Stream 2 gas pipeline from Russia to Germany.

Kariņš told CNN that the initial round of sanctions from the US and Europe was only the beginning of the Western response toward Moscow if Putin escalates further in Ukraine.

“I think that what we're seeing now is the first wave of sanctions. So Putin moves military units into Ukraine, the democratic world responds immediately, within one day, and across all the time zones, with coordinated and very deep sanctions,” he said. “If there would be more moves, there would be more sanctions, and they will only be cutting deeper and deeper.”

On Wednesday, Ukraine's parliament said it was “dealing with a cyberattack” on its website, a member of Ukraine's parliamentary press team confirmed to CNN.

Internet monitor NetBlocks tweeted that Ukraine's Ministry of Foreign Affairs, Ministry of Defense, Ministry of Internal Affairs, Security Service and Cabinet office websites have been “impacted by network disruptions.”

With the threat of a full-scale Russian invasion looming, Ukraine's National Security and Defense Council announced Wednesday that a State of Emergency would be introduced across all parts of the country under government control. The measure is expected to be approved by the Ukrainian Parliament within 48 hours and would last for 30 days, with the possibility of being extended for an additional 30 days.