The phrase "alert border" is not a standard expression in written English and may not convey a clear meaning without context.
It could potentially be used in contexts related to security or notifications, but clarity would depend on additional information.
Example: "The system triggered an alert border when unauthorized access was detected."
Alternatives: "warning boundary" or "security alert zone".
An alert border agent in Chicago turned away a Jordanian who later carried out a huge suicide bombing in Iraq.
It was, after all, an alert Border Patrol guard, not anyone in Washington, who foiled the so-called millennium plot to bomb the Los Angeles airport.
Smart-dust proponents envision such sensors being used to monitor forests for fire, warn soldiers of dangerous substances on the battlefield and alert border guards to activity in remote areas.
e-Borders Raytheon is helping countries like the U.K. set up electronic networks that can double-check passenger lists from rail, sea or air carriers against names on a watch list and alert border agents.
The tensions between the Orthodox rabbi and his smoldering daughter mirror the social and political conflicts that galvanize the film's characters into a state of high alert bordering on paranoia.
I have alerted Border Patrol and Military that this is a National Emergy.
Regulators also alerted border inspectors to watch for attempts to import domperidone and told them to confiscate the drug if they find it.
Patrick E. Tyler (NYT) AFRICA SUDAN: ALERT ON BORDER -- Sudanese troops went on alert as officials said Eritrean troops and Sudanese rebels had gathered in large numbers on Eritrea's side of the border.
Another piece of evidence had emerged months before the bombing, when an alert Saudi border agent noticed something suspicious about a car coming from Jordan — it was too close to the ground — and discovered that it was packed with explosives.
A lockdown in the city has been lifted, and schools opened Wednesday, but the country remains on high alert, with border controls tightened and extra security at the other Christmas markets around France.
Air Canada security duly alerted the border agency, which took the man into custody after the plane had landed.
