JAKARTA, July 26 (Reuters) - A strong undersea earthquake hit North Maluku province in the east of the country on Thursday, triggering a tsunami warning, a telephone text message from the country's meteorology agency said. The agency said the quake measured 6.6 on the Richter scale, while the U.S. Geological Survey put the quake at magnitude 7.4 and said the epicentre was 88 km (55 miles) deep.