Aid agencies warn of a humanitarian disaster as Omar al-Bashir calls the arrest warrant a "conspiracy."
The buildup in Ciudad Juárez, an entry point for drug smuggling on the US border, is meant to stop vicious fighting between drug cartels.
Defense Secretary Gates said Tehran was not close to having a bomb. A new report in which senior advisers to Obama participated urges further sanctions.
The claim by Al Qaeda in the Islamic Maghreb that it holds hostages kidnapped more than a month ago fuels fears that the group is expanding its reach.
Despite Langerado's cancellation last week, festival organizers remain bullish.