NEW ORLEANS, Louisiana (AFP) - Embattled BP boss Tony Hayward has handed off the daily management of the Gulf of Mexico oil spill, as the British energy firm was assailed by its partner for reckless conduct. BP chairman Carl-Henric Svanberg said chief executive Hayward, a Briton, was handing over the running of the containment efforts to another top BP official, Bob Dudley, an American. Right after the explosion (Hayward) went out there and he has been leading the response ever since, Svanberg told Sky News. I think everyone believed it to be something we could deal with faster, then he would come back. And now hes been around for eight weeks, hes now handing over the daily operations to Bob Dudley, he told the British broadcaster. The handover had been announced earlier this month, but no timing had been given. The announcement came a day after Hayward was pilloried by US lawmakers investigating the April explosion that destroyed a BP-leased rig off the southern US state of Louisiana. BP also reported progress on drilling the first of two relief wells to permanently plug the massive leak spewing tens of thousands of barrels of oil into the Gulf of Mexico. Kent Wells, a BP senior vice president, said the first relief well was now 200 feet (61 meters) from the ruptured well as it heads towards the bottom of the sea floor. But officials cautioned that despite the relief wells proximity to the existing well and the fact that BP is some 11 days ahead of schedule, the firm still needs until early August to finish the work before heavy drilling fluids can be pumped into the existing well. Meanwhile, a co-owner with BP in the well, Anadarko Petroleum, said BP should pay the costs of cleanup because of its reckless conduct, prompting a testy exchange between the two companies. In a statement, Anadarko chairman and chief executive Jim Hackett said: The mounting evidence clearly demonstrates that this tragedy was preventable and the direct result of BPs reckless decisions and actions. BPs behavior and actions likely represent gross negligence or willful misconduct and thus affect the obligations of the parties under the operating agreement, the Anadarko chief said. BP said in a separate statement that it strongly disagrees with these allegations from Anadarko and will not allow the allegations to diminish its commitment to the Gulf Coast region. BP said that Anadarko is refusing to accept responsibility for oil spill removal costs and damages despite a written operating agreement stating that the parties would share the costs of operations, including the cost to clean up any spill from the well. The news capped a nightmare week for the British energy giant that has left its public image in tatters, seen its shares rocked on the stock market and its top executives hauled to the White House. To the frustration and anger of a House of Representatives panel, Hayward repeatedly refused to be drawn on the causes of the explosion and whether there had been any negligence on BPs part, prompting lawmakers ridicule and scorn. US experts believe between 35,000 and 60,000 barrels of oil are spewing into the Gulf every day from the ruptured wellhead, and creeping ashore in four southern US states, shutting down the fishing industry and sullying tourist beaches. BP executives agreed after talks with President Barack Obama this week to set up a 20-billion-dollar escrow fund to help pay for the clean-up and compensation claims from Gulf residents facing economic ruin. But in more bad news for BP, a top credit agency slashed its creditworthiness because of the worsening impact of the disaster on its finances. Meanwhile Friday, Hollywood actor Kevin Costner joined forces with BP to launch the oil firms use of 32 centrifugal oil-water separator machines from his company, Ocean Therapy Solutions, that the star says will accelerate clean-up of oily water from the gushing Gulf leak. Used together with other oil spill collection operations, Costners V-20 technology will eventually help BP process up to 128,000 barrels of oily water daily from Gulf waters and polluted shorelines, said BP Chief Operating Officer Doug Suttles.