In an open letter addressed to world leaders attending Wednesday's Middle East conference in Rome, Amnesty said that foreign governments should support a UN Security Council arms embargo and prevent weapons transfers to Israel and Hezbollah.
More than 400 people have been killed and tens of thousands have been displaced as the conflict between Israel and Hezbollah shows no signs of abating.
Amnesty said governments should also dispatch immediate aid to civilians caught in the fray, terming the conflict a "humanitarian disaster".
"Intentionally directing attacks against civilians and civilian objects and launching indiscriminate and disproportionate attacks are war crimes," the letter stated.