(Adds terminal reopens)

LONDON, July 1 (Reuters) - British authorities evacuated part of London's Heathrow airport on Sunday while police investigated a suspect package and later reopened the terminal after security officials declared the area safe.

The suspect bag was in the departures section of Terminal 3, which handles long-haul flights from the airport. British police are on high alert after a fuel-loaded jeep was rammed into Glasgow airport on Saturday.

"(Airport operator) BAA can confirm that the incident in Terminal 3 has been cleared. Passengers are being allowed back into the terminal," BAA said in a statement.

"The incident has caused some (traffic) congestion in the area and passengers are urged to use public transport wherever possible."

AlertNet news is provided by