KYIV, Ukraine (AP) U.S. President Joe Biden warned Thursday that Russia could still invade Ukraine within days and Russia expelled the No. 2 diplomat at the U.S. Embassy in Moscow, as tensions flared anew in the worst East-West standoff in decades.

NATO allies accused Russia of misleading the world by saying it was returning some troops to their bases but instead moved in thousands of new ones. The pullout pledge was among Russian gestures this week that briefly cooled temperatures . Russia is believed to have some 150,000 military forces around Ukraines borders, raising fears of a new war in Europe.

Tensions also spiked Thursday along the line that separates Ukrainian forces from Russia-backed separatists in the countrys east, with both sides accusing each other of intensive shelling in a long-simmering conflict that has killed 14,000 people.

In a surprise blow to diplomacy, Russia ordered the deputy chief of mission at the U.S. Embassy in Moscow, Bart Gorman, to leave the country, the State Department said. It called the move unprovoked and an escalatory step. Russia did not say why he was expelled.

Doubts escalated in the West over what exactly Russia is doing with its troops around Ukraine including an estimated 60% of the overall Russian ground forces and about President Vladimir Putins overall intentions.

Bidens comments on the Russian threat were some of his starkest to date, suggesting the administrations perilous assessment of the situation.