U.S. President Barack Obama has given the go-ahead to start drone surveillance over Syria in an effort to keep an eye on the Islamic State, which would also make it easier for possible airstrikes.

The Islamic State, a militant group also known as ISIS, recently has taken control of large swaths of territory in Syria, including an air base in the Raqqa province, according to Bloomberg Businessweek.

The U.S. has launched airstrikes against ISIS in neighboring Iraq, but White House Spokesman Josh Earnest said that Obama has not decided if he will expand those airstrikes into Syria.

A U.S. official who asked not to be named said that the drones have already started surveillance in Syria. Prior to the authorization of drones, the U.S. already had started gathering intel on locations of ISIS leaders and troops, CNN reported.

ISIS has been especially active in Iraq during the past two months, but over the weekend it forced Syrian forces out of the Raqqa air base and now has control of most of the province. The siege led the Syrian government to call on the international community to take action against the Islamic State.

Raqqa is the first province that is completely outside the control of the Syrian government and now ISIS can focus more of its attention on the adjacent Allepo province, a strategic region of the country.

"(Seizing Raqqa) means the group can keep moving forward to Aleppo, which is a strategic goal as ISIS drives relentlessly toward the coastline," said Theodore Karasik, director of research at the Institute for Near East and Gulf Military Analysis in Dubai. He added that Aleppo's airport is vital to the Islamic State's economic survival as it would allow them to import necessities.

Syria warned the U.S. not to take unilateral action against ISIS, saying that any strike made without consulting the Syrian government would be an act of aggression.

But Earnest said that the U.S. government doesn't recognize President Bashar al-Assad as the leader of the Syrian state and has no intention of coordinating with his government. It was only a year ago that the U.S. was weighing the option of attacking Assad's government.