The $300 million in new weaponry the United States is sending to Ukraine, the first American military aid package in months, will help Ukraine hold off Russian troops for a few weeks, analysts say, but it will not change the overall situation on the battlefield, where Moscow currently has the advantage.

Ukraine has long said that it would lose more ground to Russia unless it received more weapons and ammunition, but a robust $60 billion aid package has been bottled up in the House for months by conservative Republican lawmakers. That has left frontline Ukrainian troops vulnerable to long-distance glide bombs dropped from Russian aircraft and intense artillery attacks.

Here’s a look at the current situation.

What did the U.S. promise, and will it make a difference?

American military support for Ukraine dried up in late December, and the White House has been looking ever since for ways to circumvent the logjam in the House. The new package, announced on Tuesday, does that by drawing on cost savings in Pentagon contracts.

The package will provide Ukraine with an array of desperately needed weapons. These include Stinger missiles to target aircraft, which Russia has increasingly used to support ground assaults, artillery rounds to keep Russian troops at bay and anti-tank weapons to repel mechanized assaults.

“This ammunition will keep Ukraine’s guns firing for a period, but only a short period,” said Jake Sullivan, the U.S. national security adviser. “It is nowhere near enough to meet Ukraine’s battlefield needs, and it will not prevent Ukraine from running out of ammunition.”