(Photo : YASUYOSHI CHIBA/AFP via Getty Images)
Ukrainian soldiers ride on an armored vehicle.

Russian forces are likely to ramp up their attacks on Ukraine territory to take advantage of the final weeks before U.S. aid finally makes its way to the front lines. 

The Ukrainian front line will continue to deteriorate, particularly if Russian forces increase their attacks to take advantage of the limited window before the help arrives, according to The Institute for the Study of War (ISW), adding that  it is likely that Russian forces will intensify offensive operations and missile and drone strikes. 

The U.S. House passed the aid bill on Saturday and the Senate is expected to act on it soon to send it to President Biden for approval.

Pentagon Spokesperson Brigadier General Patrick Ryder believes that the United States will be able to "rush the security assistance in volumes" soon after the aid package is approved.

The Pentagon says it will begin moving ammunition, artillery shells and air defense assets quickly once Congress approves the aid.

But the ISW says it will take several weeks for any new weapons to reach the front lines in Ukraine and it will be June before Ukraine will be in an improved position.

Despite the time until Ukrainian troops can be rearmed, the ISW thinks they will likely be able to blunt the current Russian offensive if U.S. assistance arrives "promptly."

Ukrainian President Volodymyr Zelenskyy told NBC News the swift delivery of US military aid to Ukraine could allow Ukrainian forces to stabilize the frontline and seize the initiative.

Russia is reportedly facing its own shortfalls.

Ukrainian military analyst Petro Chernyk said Sunday that the Russian military has been using small two- and four-seat buggies similar to golf carts to move troops to the frontline to make up for a shortage of military transport vehicles.