Qatar said on Monday it was still studying the purchase of Russia’s S-400 missile air defense system, adding the potential deal – reportedly opposed by Saudi Arabia – was none of Riyadh’s business, Reuters reports. Foreign Minister Sheikh Mohammed bin Abdulrahman al-Thani also said there was no sign of a thaw in a Gulf row over allegations by Saudi Arabia and some other Arab states that Qatar supports terrorism. Doha denies the charges. “There is a discussion for procurement of various Russian equipment but there is no understanding as of yet as to this particular equipment,” Sheikh Mohammed told a joint news conference with Russia’s Foreign Minister Sergey Lavrov. Qatar’s emir Tamim bin Hamad Al Thani held talks on Monday with Lavrov in Doha, discussing regional and international developments, especially the situation in Syria, Libya and Somalia.