The US threatened unilateral action against Iran after Russia vetoed a UN Security Council resolution on Tehran’s failure to stop its weapons from reaching Houthi rebels in Yemen. "If Russia is going to continue to cover for Iran then the US and our partners need to take action on our own,” said US ambassador to the United Nations Nikki Haley on Monday. “If we’re not going to get action on the council then we have to take our actions.” Ms Haley did not specify what kind of action could be taken. Russia on Monday vetoed the resolution that would have...