Russia has repositioned artillery near the disputed city of Aleppo, several U.S. officials told Reuters. Despite withdrawing some fixed-wing aircraft in March, Russia has also bolstered its forces in Syria with advanced helicopter gunships, and renewed airstrikes against moderate opposition groups, said U.S. officials, speaking on condition of anonymity.
The Russian reassertion of military backing has prompted some U.S. officials to warn that a failure to respond would be seen by Moscow as a fresh sign of American timidity. That, they say, could encourage Russia to escalate challenges to U.S. and allied militaries through more provocative Russian air and naval maneuvers.
They also contend that a U.S. failure to respond would further damage Washington’s relations with Saudi Arabia and other Gulf states seeking to oust Assad, and with Turkey, which has been firing artillery at Islamic State targets in Syria.
The answer, they argue, is stepped-up U.S. support for moderate Syrian rebel factions with more anti-tank missiles and grenade launchers sent through third countries.
However, other officials, including National Security Advisor Susan Rice, have vetoed any significant escalation of U.S. involvement in Syria, the officials said.
“Rice is the fly in the ointment,” said a person familiar with the internal debate.
Obama himself has long been reluctant to deepen U.S. involvement in the war, saying last October that Washington would not get drawn into a “proxy war” with Moscow. His administration has focused more on pressing the fight against the militant Islamic State group, which controls a swathe of northeastern Syria.
The White House declined comment about any internal debate on Syria or Putin’s intentions.