The US accused Russia on Wednesday of continuing to intensify its army buildup along Ukraine's border and issued new warnings against any "aggression" by Moscow.

The US previously urged Russia to withdraw from the borders, warning that G7 and allies would impose "tough measures" if Moscow "abandons diplomacy."

A US State Department spokesperson told AFP that "Russia continues escalating and has not reversed its troop buildup."

The spokesperson reiterated that further action against Ukraine would "carry a severe price," adding that the US and allies are monitoring the situation. 

The US' statement came amid German claims of further troop movements on the border between Russia and Ukraine.

"We strongly urge Russia to de-escalate by pulling back troops from its border with Ukraine," the State Department spokesperson added.  

"Our goal is de-escalation through diplomacy; the US is ready to engage in diplomacy in January through multiple channels."  

Russia could face 'massive consequences' if it invades Ukraine: EU

European Union leaders jointly warned Russia would face "massive consequences" if it "invades" Ukraine, which could see the 27 nation bloc coordinating with allies to take measures against Russia.

The EU's warnings came amid western claims of a troop buildup on the border with Ukraine and of preparing for a military invasion - accusations Russia has long been denying.

The West had previously threatened Russia with "heavy sanctions," but President Vladimir Putin said earlier this month Moscow pursues a peaceful foreign policy; however, it has the right to defend its security.

US and NATO claim no aggressive intent with Russia

According to White House spokesperson Jen Psaki on Wednesday, the US and NATO have no aggressive intentions regarding Russia.

During a press briefing, Psaki disclosed that "NATO is a defensive alliance. We don't have aggressive intent with Russia. The United States doesn't, neither do NATO partners."