Ukraine’s Foreign Minister Dmytro Kuleba flew to Brussels for talks with Stoltenberg a day after Kyiv accused the Kremlin of ignoring its request for talks between the two countries’ presidents over a build-up of Russian troops near its border.

“In recent weeks Russia has moved thousands of combat-ready troops to Ukraine’s borders, the largest massing of Russian troops since the illegal annexation of Crimea in 2014,” Stoltenberg said.

“Russia must end this military build-up in and around Ukraine, stop its provocations and deescalate immediately,” he said at a news conference with Kuleba. Kuleba said Kyiv wanted a diplomatic solution.

Kyiv and Moscow have traded blame over the worsening situation in the eastern Donbass region, where Ukrainian troops have battled Russian-backed forces in a conflict Kyiv says has killed 14,000 people since 2014.

The West has expressed concern in recent weeks over a huge build-up of Russian forces close to Ukraine’s eastern border and in Crimea, which Russia annexed from Kyiv in 2014.

U.S. Secretary of State Antony Blinken arrived in Brussels on Tuesday and is due to hold talks later on Tuesday with Kuleba. Kuleba called for further economic sanctions against Moscow and more military help to Kyiv.

“At the operational level, we need measures which will deter Russia and which will contain its aggressive intentions. This could be … a new round of sanctions which would raise the price of Russian aggression,” Kuleba told a news conference.

Separately, two allied diplomats said Stoltenberg would chair an emergency video conference with allied defence and foreign ministers on Wednesday. Blinken and U.S. Defense Secretary Lloyd Austin are expected to be present at NATO headquarters in Brussels to brief the other 29 allies on Ukraine, as well as on Afghanistan, the diplomats said. (Reporting by Robin Emmott and Sabine Siebold, Editing by Gabriela Baczynska, William Maclean)