A prominent human rights group says Hamas militants committed war crimes when they launched rocket attacks against Israel.

A Human Rights Watch spokesman said Hamas rocket attacks that targeted Israeli citizens were "unlawful and unjustifiable".  

A new report released by the group says Hamas militants fired rockets that placed about 800,000 Israeli civilians at risk and killed two Israeli girls.     

It also says militants that launched rockets from densely populated areas placed Gaza civilians at risk of Israeli counter strikes.

The report focuses on Hamas tactics used just before and during Israel's three-week offensive in Gaza, from last November to mid-January.

Human Rights Watch and other rights groups have repeatedly accused Israel of committing war crimes.  At least 1,300 Palestinians and 13 Israelis were killed during the Israeli offensive.

Some information for this report was provided by AFP and AP.