Syrian dictator Bashar al-Assad can continue to count on military support from Moscow, as Russian President Vladimir Putin insisted the aid was needed "to counter terrorist aggression."

Assad's regime has been involved in a civil war with opposition militants and the ISIS terror group since the early spring of 2011. More than 200,000 people are believed to have died in the conflict so far, and the war has produced more than 4 million refugees, according to U.N. statistics.

"We support the government of Syria in its effort to counter terrorist aggression," Putin noted on Tuesday at a security summit in Dushanbe, the capital of the Central Asian republic of Tajikistan, the Wall Street Journal reported. "We provide and will continue to provide military assistance. We call on other countries to join with us," he added.

The White House, however, said that Russia's support for Assad was "counterproductive" and that the United States would like to see more "constructive engagement" from Moscow with the coalition against ISIS, spokesman Josh Earnest said, according to the BBC.

Russia's backing of the Assad regime are strategic, the British news channel commented, and are linked to the Kremlin's concerns about militant Islam and wider trends in the region. The situation in the Arab country would have been "worse than in Libya" had Russia not supported its leadership, Putin argued in Tajikistan.

Assad's army, meanwhile has suffered setbacks in recent months, and U.S. officials believe the buildup may be a prelude to possible Russian airstrikes against ISIS and other forces looking to oust the Syrian dictator, the Wall Street Journal said. Nevertheless, Russian officials have played down the deliveries of military hardware to Syria, the newspaper added.

State department spokesman John Kirby reiterated the U.S. view that the Russian aid would not help end the civil war, Agence France-Presse noted.

"It certainly appears as though they are continuing to support the Assad regime," Kirby said. "What we would like to see is movement towards a political transition in Syria, and we still believe there's an opportunity to pursue that kind of transition in concert with Russian authorities."