ROUGH CUT. NO REPORTER NARRATION.br br A cross-border deal to explore for oil in the deep water of the Gulf of Mexico is inked at the G20 summit on Monday (February 20).br br U.S. Secretary of State Hillary Clinton and Mexican President Felipe Calderon sign the agreement to allow U.S. firms and Mexican oil monopoly Pemex to exploit deep water oil resources that straddle the countries maritime borders.br br Mexico - the world's No. 7 oil producer - has drilled less than 20 wells in its territorial waters in the Gulf.br br A Pemex director has said the company plans to drill six or seven new deep water wells in the next year.br br Safety concerns loom large after the explosion of BP's Deepwater Horizon rig in April 2010 that killed 11 workers and spewed more than 4 million barrels of oil into the Gulf.