5 Things to Know This Morning

— -- Your look at the five biggest and most buzz-worthy stories of the morning.

1. US Airstrikes Against ISIS Targets Begin in Syria

American airstrikes against up to 20 ISIS targets began Monday night in Syria, according to Pentagon officials.

Several Arab nations are involved in the ongoing U.S.-led operation, a defense official said. A diplomatic source identified the nations as Jordan, Saudi Arabia, Bahrain, Qatar and the United Arab Emirates.

Another U.S. official said the Arab nations will be dropping bombs, not just providing support. Up to 20 locations have been targeted in the operation, many of the sites in Raqqa, the official said.

2. Hannah Graham Searchers Return to Jesse Matthew's Apartment

A warrant was issued Monday to carry out a second search of the apartment belonging to a man who police say was the last person to be seen with missing University of Virginia student Hannah Graham.

Charlottesville police carrying out the search were seen Monday at the apartment of Jesse Matthew. They also released a wanted poster for Matthew, saying that he may be in possession of his sister's car. They said that he has known associates in Washington D.C., Maryland, Pennsylvania and New York in addition to his home state of Virginia.

3. White House Fence Jumper Had 800 Rounds of Ammo in Car

White House fence jumper Omar Gonzalez had more than 800 rounds of ammo in his car plus two hatchets and a machete, prosecutors said today as Virginia authorities revealed the Army veteran was arrested last July and charged with possession of a sawed-off shot gun and eluding police in Wythe County, Virginia.

Police also found "several assault rifles" in the vehicle at the time of his July arrest, according to a criminal complaint obtained by ABC News.

4. Second Grader, 3 Others Attacked by Rabid Fox

Four people were bitten by a fox Monday, including a second grade boy who was attacked during an outdoor gym class, and the boy's gym teacher who ran to his aide and ripped the animal off him.

5. Kris Jenner Files to Divorce Bruce Jenner

Kris Jenner is ending her 22-year year marriage to Olympic gold medalist Bruce Jenner.

The "Keeping Up With the Kardashians" matriarch filed for divorce on Monday in Los Angeles, citing irreconcilable differences.