I seem to recall seeing some news story that the US would provide Ukraine with modern anti-tank weapons. I wonder if that has happened?
OTOH, it appears Ukraine manufactures their own:
http://defense-update.com/20131108_poland-interested-ukraine-anti-tank-missiles.html#.U-15v5AU-70
The Ukrainians make a large variety of pretty modern weapons. I think their main problem is no money.
My understanding is that the U.S. has not provided Ukraine with any offensive weapons, although it has asked.