The new operation would include U.S. troops on the ground in Mexico striking drug labs and cartel leaders, according to current and former U.S. officials, though a deployment is not imminent.

The US military is upgrading a Cold War base in the Caribbean it abandoned 20 years ago. Experts say it’s a step towards sustained operations in the region.

With millions geared up to vote in a key off-year election, including a hotly watched redistricting measure in California, the Donald Trump administration has ignited fierce backlash by deploying fede...