President Obama said it was an important step in preventing the spread of weapons of mass destruction, but added that Syria must still destroy its other weapons production facilities.
The previous cease-fire lasted five days and expired at midnight. Unlike other deal extensions, there have been no reports of rockets fired or Israeli action. Talks continue with mediators in Egypt.
Using a new technology, scientists have created a vaccine for an emerging mosquito-borne virus. The vaccine was safe and produced some degree of immunity in a preliminary study.