sentences:  The Saudis' increase of oil production to stabilize the oil price and the support of anti-communism have all contributed to closer relations with the U.S.In January 1979, the U.S. sent F-15 fighters to Saudi Arabia for further protection from communism.Furthermore, the U.S. and Saudi Arabia were both supporting anti-communist groups in Afghanistan and struggling countries, one of those groups later became known as the Al-Qaida terrorist organization.