Ukraine urged Nato on Wednesday to prepare economic sanctions on Russia and boost military cooperation with Kyiv as the country joined the Western alliance for talks about how to deter Russia from a renewed attack after massing troops close by.

Ukraine, a former Soviet republic that now aspires to join the European Union and NATO, has become the main flashpoint between Russia and the West as relations have soured to their worst level in the three decades since the Cold War ended.

"We will call on the allies to join Ukraine in putting together a deterrence package," Ukraine's Foreign Minister Dmytro Kuleba told reporters...