A subsidiary of U.S.-based ExxonMobil Corp. has begun exploratory drilling for oil and gas off Guyana's coast in South America.

The launch of the $300 million project comes amid heavy objection from Venezuela's government, which claims the area being explored belongs to it.

ExxonMobil country manager Jeff Simmons said Friday that drilling will last about 60 days.

Venezuela has long claimed two-thirds of Guyana's territory as its own and has taken action in the past. About two years ago, Venezuela detained a ship conducting a seismic study under a concession from Guyana. It was released after a week.