The headlines and summaries of the editorials and main articles of Tehran's Principlist papers this morning: Kayhan: The talks between Iran and the Group 5+1 is reaching its most crucial and sensitive days. The West is trying to get more concessions from Iran in lieu of lifting the unilaterally-imposed sanctions against Tehran. The most important tactic to which the Iranian statesmen can resort to foil the western plots is resistance economy. The Iranian team of negotiators should not be deceived by the West's plots. Resalat: The Iranian negotiating team should merely focus on nuclear issues in their talks with the world powers (the US, Russia, China, France and Britain plus Germany). Any other attempt to include issues other than technical matters in the talks is unacceptable. The Iranian negotiators should move within the framework of the guidelines of Supreme Leader of the Islamic Revolution Ayatollah Seyed Ali Khamenei in a bid not to allow the western countries to cross the redlines of the Islamic Republic. Javan: The US has imposed sanctions on Russian officials, including 38 officials close to Russian President Vladimir Putin, and 8 companies and one bank on the pretext of crisis management in Ukraine. Meantime, Russia called the western sanctions as inefficient while warning the West that it would take retaliatory measures. Imposing sanctions on 11 US officials was Russia's first reaction. It is quite evident that Russia intends to control the trend of the increasing US and European sanctions through retaliatory measures. What Russia has done is in fact within the framework of the international law. Siasat-e Rouz: The US has ushered in new efforts to undermine the Syrian army's victories in the battlefield. The Syrian opposition leader Ahmad Al-Jarba in his recent visit to Washington has been promised by US Secretary of State John Kerry that the Obama administration will supply the Syrian opposition with increasing logistical and financial assistance.