Hamas is designated as a terrorist organization by the United States and the European Union.
What Is Hamas?
It was founded in 1987 by Sheikh Ahmed Yassin, a Palestinian religious leader with ties to the Muslim Brotherhood.
Hamas published a charter in 1988 calling to "obliterate" Israel and establish a new Islamic society
The United States designated Hamas as a foreign terrorist organization in 1997.
Hamas has ruled the Gaza Strip since 2006 after winning local elections and has faced a 16-year blockade by Israel and Egypt.
The surprise attack on Saturday was the deadliest since 2014 when tensions led to a seven-week retaliation.
In May 2021, Hamas launched about 1,600 rockets into Israel, leading to a ceasefire negotiated with the help of the United States and Egypt.
President Joe Biden pledged aid to Gaza for reconstruction while ensuring it doesn't benefit Hamas.
The United States has provided significant military aid to Israel since the 1990s, with an annual increase to about $3.8 billion in 2019.