Despite having a charter that called for the murder of Jews across the world, Israel actually bolstered this fundamentalist religious group, universally known as Hamas, during its formative years in the 1980s. After occupying the Gaza Strip, Israel encouraged the rise of Islamists as a way of undercutting the secular Palestine Liberation Organization, which Israel had always viewed as the greater threat. One of the individuals who Israel helped was Sheikh Ahmed Yassin, leader of the Muslim Brotherhood in the Gaza Strip, who had organized a charity that built mosques, clubs, and schools there.
Less than 20 years later, the political situation in the Palestinian territories became far more complicated. Although the extent of cooperation between Hamas and the Palestinian Authority during the 90s and early 2000s was disputed, Hamas was voted into power in elections in the Gaza Strip and the two sides eventually engaged in a civil war in 2007, with Hamas crushing the PA's forces in the Gaza Strip and becoming the sole power in that territory.