The Wall Street Journal quoted American officials and diplomats as saying that the Central Intelligence Agency is planning to provide the insurgents with US weapons within a month.
The weapons are being moved to Jordan from a network of warehouses, the report added without giving any explanation about their locations.
The officials who have been briefed by the CIA said that Saudi Arabia and other US regional allies are also contributing to the plan by sending weapons to the militants.
Arms shipments are underway as US secretary of state John Kerry claimed on Wednesday that Washington believes there are no military solutions to the crisis in Syria and political means are the only way to end the bloodshed.
His comments however seemed contradictory to his previous call, in a conference in Doha, for starting urgent shipment of arms to Syria to topple the government.
The weaponry includes different types of anti-aircraft and anti-tank missiles, small arms and ammunition. It would take up to three weeks to send all the weapon consignment to Jordan.
The report also added that the US and its European and Arab allies have plans to train different groups of militants in Jordan on how to use the weapons.
The first groups of US-trained insurgents are expected to arrive in Syria in late July or early August.
According to earlier US media reports, the American military has been secretly training the militants since November last year.
The White House’s open announcement to arm and train the militants comes as the Syrian army has managed to secure some of its border towns to stop flow of foreign militants and terrorists to infiltrate the country.
Syria crisis started as pro-reform protests but with interventions by the United States, UK and their regional and Western allies it soon turned to a massive insurgency which took in numerous terrorist groups from all over Europe and the Middle East to wage one of the bloodiest wars the region has ever experienced.
The war, which many fear is turning to a “war of hatred”, has already taken more than 90,000 lives.