Iranian President Hassan Rouhani called Wednesday on the Muslim world to unite and punish the Saudi government.
Russian warplanes on Tuesday flew a bombing run from an Iranian airstrip against jihadist groups in war-torn Syria.
Oil plunged Monday a day after top producers failed to reach a deal in Doha to cap output.
OPEC warned that the world remains awash with crude ahead of a crunch meeting in Doha to discuss a production freeze to boost the oil price.
Iran's defence minister is certain the UN Security Council will not take any action over its missile tests despite calls from the Western.
Iran fired two more long-range ballistic missiles on Wednesday as it continued military tests in defiance of US sanctions and fresh warnings from Washington.
The Ministry of Foreign Affairs of Kazakhstan calls the leaders of both countries to cooperate to resolve the crisis.
Iran announced a major boost in oil production on Monday after the lifting of sanctions under its nuclear deal.
Iran sent a major shipment of low-enriched uranium materials to Russia to implement nuclear accord with world powers.
Russian President Vladimir Putin will visit Tehran for talks sure to sharpen attention on his alliance with Iran in Syria after the Islamic State group's deadly attacks in Paris.
Iran has appointed its first woman ambassador since the 1979 Islamic revolution, naming foreign ministry spokeswoman Marzieh Afkham to head its embassy in Malaysia.
Russia plans to open a $5 billion credit line for Iran to help finance infrastructure projects in the country, officials from both countries said during a visit by Moscow's energy minister.
President Barack Obama ordered the US government to take steps towards lifting sanctions on Iran, in accordance with the historic nuclear deal struck between six world powers and Tehran.
Kazakhstan is to construct its fourth oil refinery in cooperation with Iran and China.
Iran's nuclear accord with world powers won final approval in the Islamic republic with a top panel of jurists and cleric giving the green light.
Russian President Vladimir Putin's bullish entry into the Syrian conflict has worked wonders for his popularity in neighbouring Iraq, where some await "Hajji Putin" like a saviour.
Israel's prime minister savaged the nuclear deal with Iran, falling silent for nearly a minute at the United Nations in protest and offering to resume direct peace talks with the Palestinians.
Iran's President Hassan Rouhani has tried to reassure a skeptical American public that when crowds in Tehran chant "Death to America!" they don't mean it personally.
They are rivals on the campaign trail, but Republican presidential challengers Donald Trump and Senator Ted Cruz joined forces at a rally denouncing the Iran nuclear deal being debated by the US Congress.
US President Barack Obama hailed a Congressional vote allowing a nuclear deal with Iran to go ahead.