Löfven made the comments during the first official state visit of Ukrainian President Petro Poroshenko.
Speaking to reporters, Löfven said there was clear support within the European Council to prolong sanctions against Russia until it adhered to the so-called Minsk agreement, a peace plan signed by Ukraine and Russia.
"These sanctions are connected to delivery on the Minsk agreement," Löfven said.
The EU imposed sanctions on Russia over its annexation of Crimea and destabilizing role along Ukraine's eastern border with Russia.
Löfven added his government would continue to offer support for Ukraine and its internal reforms.
During the joint press conference with Löfven, Poroshenko called Sweden a "very reliable partner and friend." He also said he has "no doubt" that US president-elect Donald Trump will not recognize Russia's annexation of Crimea.
"I am absolutely sure that the new president-elect is completely strong enough in an effective cooperation with Ukraine ... no doubt," he said.