JAKARTA, INDONESIA - A POWERFUL 6.6-magnitude earthquake struck at sea off the Indonesian island of Java on Tuesday, and a tsunami warning was issued, authorities said.

There were no immediate reports of damage from the quake which struck 125km northwest of Ujungkulon in West Java at 10.07am (11.07am Singapore time), meteorological officials said.

It was recorded at the relatively shallow depth of 20km and had the potential to trigger a tsunami, Indonesian officials said.