Ukraine's Ministry of Foreign Affairs tweeted a pair of hashtags last night—#UkraineUnderAttack and #RussiaInvadedUkraine—which appear to sum up the situation on the ground, the Washington Post reports. Pro-Russia separatists backed by Russian troops, artillery, and armored vehicles are now attacking on two fronts, authorities in Kiev say, with fierce fighting along a new southeastern front. The Russian tanks and armored personnel carriers seen in the area—which would give Russia a land bridge to Crimea—appear to have come straight over the border instead of from separatist-controlled areas in eastern Ukraine, the Los Angeles Times reports. President Petro Poroshenko canceled a trip to Turkey, citing sharp aggravation of the situation in Donetsk region, as Russian troops were actually brought into Ukraine," according to a statement.
Russia has not acknowledged any troop movements. A rebel commander says there are around 4,000 Russians fighting with the separatists, but they are all volunteers. "Many former high-ranking military officers have volunteered to join us. They are fighting with us, considering that to be their duty," he tells the BBC. "There are also many in the current Russian military that prefer to spend their leave among us." The US has expressed its "deep concern" about Russian involvement in the rebel offensive. "Russia is clearly trying to put its finger on the scale to tip things back in favor of its proxies," a senior American official tells the New York Times. "Artillery barrages and other Russian military actions have taken their toll on the Ukrainian military." After days of fighting, the strategic southeastern town of Novoazovsk now appears to be under rebel control, the AP reports. (Read more Ukraine stories.)