Hamas is a Palestinian group based in the Gaza Strip. It has a political wing and an armed wing. Both are actively struggling for Palestinian independence.
Founded in 1987, Hamas has been a counter group to the Palestinian Liberation Organization (PLO) and has been internationally shunned as a terrorist organization because its military wing periodically attacks Israel and its citizens.
Israel's military has launched a series of air attacks on Palestinian territory in retaliation for an earlier rocket attack. The violence has jogged memories of the 50-day war between Israel and Hamas militants in 2014.