MOSCOW — Russia’s chief arms exporter said Friday that his company was shipping advanced defensive missile systems to Syria that could be used to shoot down airplanes or sink ships if the United States or other nations try to intervene to halt the country’s spiral of violence.

“I would like to say these mechanisms are really a good means of defense, a reliable defense against attacks from the air or sea,” Anatoly P. Isaykin, the general director of the company, Rosoboronexport, said Friday in an interview. “This is not a threat, but whoever is planning an attack should think about this.”

As the weapons systems are not considered cutting edge, Mr. Isaykin’s disclosures carried greater symbolic import than military significance. They contributed to a cold war chill that has been settling over relations between Washington and Moscow ahead a meeting between President Obama and President Vladimir V. Putin, their first, on the sidelines of the Group of 20 summit meeting in the Mexican resort of Los Cabos next week.

Mr. Isaykin’s remarks come just days after Secretary of State Hillary Rodham Clinton raised diplomatic pressure on Russia, Syria’s patron, by criticizing the Kremlin for sending attack helicopters to Damascus, and amid reports that Moscow was preparing to send an amphibious landing vessel and a small company of marines to the Syrian port of Tartus, to provide security for military installations and infrastructure, if it becomes necessary.