over the spill site in the Gulf

over the spill site in the Gulf Trying to assert leadership in the face ofMicrofiber cloth growing criticism over his handling of the spill, Obama toured the Louisiana Gulf coast, where oil has seeped into delicate marshlands and shut down much of the lucrative fishing trade.

BP (BP.L) CEO Tony Hayward flew over the Gulf to where his crew and robots worked on the "top kill" -- the injection of heavy fluids, materials and ultimately cement to seal the well one mile (1.6 km) below the surface.

Hayward said the procedure was making progress choking off the five-week-old leak that has already spewed millions of gallons (litres) of oil into the Gulf.

"We have wrestled it to the ground but we haven't put a bullet in its head yet," Hayward told Reuters while aboard a helicopter over the spill site in the Gulf.

When the top kill began on Wednesday, BP said it would need up to 48 hours to gauge its success. But Hayward extended the timeline another 24-48 hours on Friday.

He said the top kill's chance of success remained at 60 to 70 percent.

BP has called the effort to plug the hole "a "rollercoaster ride," and investors might say the same. BP shares lost 5 percent on Friday, erasing gains made on hopes for a successful top kill.

On his second visit to the Gulf in the five-week crisis, Obama faced his own steep challenge to convince Americans that he was in command as frustrated Gulf Coast residents loudly criticized federal authorities for being slow to act and offering too little assistance.

"You will not be abandoned. You will not be left behind. We are on your side and we will see this through," Obama said in a televised statement after meeting local andMicrofiber cloth state officials and inspecting the oil spill damage to the coastline.