MOSCOW (Reuters) – Russia’s Foreign Ministry said on Thursday that if the United States decided to supply Kyiv with longer-range missiles, it would cross a “red line” and become “a party to the conflict”. In a briefing, Foreign Ministry spokeswoman Maria Zakharova added that Russia “reserves the right to defend its territory”. Washington has supplied Ukraine with advanced rockets that can hit targets up to 80 km (50 miles) away, while so far holding back from publicly announcing it would send rockets with more than double that range. U.S. officials say Ukraine has promised not to use U.S. rock…