North Korea has signed off an a treaty with Russia calling for a “comprehensive strategic partnership,” Pyongyang’s state-controlled news agency KCNA reported on Tuesday. It comes as North Korean troops are in Russia fighting against Ukraine, according to Ukrainian and other military sources. In a statement, KCNA said North Korea signed the treaty, which was concluded on June 19 in Pyongyang, on Monday. It will take effect once both sides exchange their ratification documents, the agency said. Russian President Vladimir Putin signed off on the agreement on Saturday, the South Korean news agenc…