The NATO alliance will deepen its cyber warfare cooperation with its partner Ukraine, Secretary General Jens Stoltenberg said Friday, after a massive cyberattack knocked out official websites. “Allied experts in (the) country are also supporting the Ukrainian authorities on the ground,” Stoltenberg said, in a statement from NATO headquarters. “In the coming days, NATO and Ukraine will sign an agreement on enhanced cyber cooperation, including Ukrainian access to NATO’s malware information sharing platform.”