Obama promises 'relentless response' to Lousiana oil slick

US President Barack Obama on Sunday warned of an imminent "massive and potentially unprecedented environmental disaster", as a widening oil slick in the Gulf of Mexico moved to 14 km off the coast of Louisiana.

The president however said his administration would continue its "relentless response" to the oil spill caused by the sinking of an offshore rig on 20 April.

Obama said in Venice, a staging ground for efforts to fight the oil slick, that the administration would spare no resource to clean up whatever damage had been caused. He had earlier met up with state and federal officials in Lousiana.

Obama said that from day one the administration had prepared and planned for the worst while hoping for the best. He added that the administration would not rest until the leak had been plugged at the source, the oil cleaned up and people in the region were able to go back to their livelihoods.

At the same time he made it clear that the rig owner BP Plc would be required to pick up the tab for the costs. He emphasised that BP was responsible for the leak and would be paying the bill.

Though the spill is likely to boost opposition to offshore drilling, analysts say it would not affect the southern state's embrace of big oil companies.