The United States is considering economic sanctions against Syria's oil and gas sectors. In a telephonic conference with reporters, two senior White House officials said the US is also considering if war crimes charges can be brought against Syrian president Bashar al-Assad as part of a larger diplomatic effort to force his government to end its crackdown on dissent. The diplomatic wrangling comes as Syrian security forces on Friday killed at least 18 anti-government protesters who demonstrated in the streets with renewed calls for President Assad's resignation.