Asked about the violence in Libya last week that led to the death of Ambassador Christopher Stevens, President Obama said the administration's top priorities are to "refortify" security at US embassies abroad and bring those responsible to justice.
He denounced the anti-Muslim video which triggered the violence, but said it was not an excuse:
The message we have to send to the Muslim world is that we expect you to work with us, to keep our people safe, and as offensive as this video was - and obviously we denounced it, the United States government had nothing to do with it - that's never an excuse for violence.
More top news
It will be a chilly day for many parts with the highest temperatures, about 10 Celsius (50F) in the far northwest.
The social site has been overhauling many of its policies in recent weeks following repeated criticism over how it handles abusive content.
Niraparib is a PARP inhibitor belonging to a new class of drugs that target cancers with defective DNA repair systems.