WASHINGTON D.C.: After several high-profile near collision incidents, the US Federal Aviation Administration (FAA) has issued a safety alerts to airlines, pilots and others, which stressed the "need for continued vigilance and attention to mitigation of safety risks."

"While the overall numbers do not reflect an increase in incidents and occurrences, the potential severity of these events is concerning," the FAA said.

Since January, six serious runway incursions have been recorded, forcing the agency to organize a safety summit.

"Operations should evaluate information collected through their safety management processes, identify hazards, increase and improve safety communications with employees and enact mitigations," the FAA alert stressed.

Several serious close calls are being investigated by the National Transportation Safety Board (NTSB). These include a near collision in January between FedEx and Southwest Airlines planes in Austin, Texas, and a runway incident involving an American Airlines plane at New York's John F. Kennedy Airport.

The US could not wait for the next "catastrophic event" before addressing the uptick in aviation close calls, said Transportation Secretary Pete Buttigieg last week.

The board had previously issued seven recommendations on runway collisions that had not been acted on, stressed NTSB Chair Jennifer Homendy.

During the summit, she noted, "There have been far too many close calls. These recent incidents must serve as a wake-up call."

Also, acting FAA Administrator Billy Nolen said he was forming a safety review team in a "call to action" memo last month.

There has been no major fatal US passenger airline crash in the US since February 2009.