The French military began reconnaissance flights last week above Syrian Islamic State positions in response to the migrant crisis created by the country's civil war, which has caused more than 4 million Syrians to flee.
"We announced reconnaissance flights would be carried out allowing us to envisage strikes if necessary ... and it will be necessary," Hollande said Monday at a press conference.
France did not participate in U.S.-led coalition airstrikes against the Islamic State in Syria mostly due to fear that such action might maintain the regime of Syrian President Bashar Assad, The Guardian reported. Hollande recently said the only solution to the Syrian crisis is to remove Assad as leader.
France is part of the coalition attacking the Islamic State in Iraq. About 56 percent of French people support a military operation against the Islamic State in Syria, although most do not believe a military intervention would solve the crisis.