The Rossiya-24 channel showed Salman's plane arriving at Vnukovo airport outside the Russian capital. "I " m sure your visit will boost the ties between our countries", Putin added.
The Russian president also said he was confident the visit by Salman would give a fresh impetus to the development of bilateral ties with Riyadh.
The announcement of the Saudi investment comes as the Saudi Minister of Energy and Industry, Khalid Al-Falih, claimed that the cooperation between the Kingdom and Russian Federation has "breathed life back into [Organisation of Petroleum Exporting Countries] OPEC", which would help raise the price of oil for the benefit of both countries.
"Russia's energy balance is one of the cleanest among the world's largest economies", the president said while addressing a plenary session of the Russian Energy Week (REW), which kicked off in Moscow on October 3. The agreements reached between the two countries are spread into cooperation in the military and technical spheres, energy and investment.
Washington and Riyadh inked in May $110 arm deal.
Russian Foreign Minister Sergei Lavrov in an interview has said that the visit of King Salman would contribute to stability in the Middle East.
Russian Federation and Saudi Arabia remained at odds on the conflict in Syria.
"The Saudis want help on Iran, and Russia wants trade and investment", said Mark N. Katz, a Russia-Middle East relations analyst at George Mason University.
Saudi King Salman is in Moscow with a delegation that includes domestic military and oil experts.
Several investment deals are expected to be negotiated.
The approval opens the way for Saudi Arabia to purchase 44 Terminal High Altitude Area Defense (THAAD) launchers and 360 missiles, as well as fire control stations and radars.
Saudi King Salman's visit to Russian Federation "is a historical one" as it shows that "the two parties are ready to open a new era", Hassan Nafaa said.
"Salman and Putin are expected to discuss major defense and energy contracts, as well as extending oil production cuts ahead of the OPEC [Organization of Petroleum Exporting Countries] oil cartel meeting in November", notes AFP.
A slew of investment agreements would be signed during King Salman's trip and plans for a $1-billion fund to invest in energy projects are likely to be finalised then, as part of efforts by two of the world's biggest oil producers to expand cooperation. Relations improved under the Trump administration, but Washington's focus in Syria continues to be on fighting the Islamic State group, not on ousting Assad.
A Saudi plane is travelling daily between Riyadh and Moscow to transport supplies, said the person, who said that 800kg of food has been brought in.