TAIPEI, Feb 24 (Reuters) - China's military is learning from Russia's invasion of Ukraine that any attack on Taiwan would have to be swift to succeed, but the Taiwan Strait would make that challenging, the island's defence minister said on Friday. He said even if Chinese forces were planning a speedy attack, they would face difficulties trying to take the island in a sudden move as they would have to cross the Taiwan Strait that separates the two. "Taiwan will continue to firmly support Ukraine," the island's president, Tsai Ing-wen, wrote on her Facebook page on Friday, to mark the first anniversary of the invasion