Robot submarines have made halting progress in BP‘s latest bid to siphon off oil leaking from its ruptured wellhead in the Gulf of Mexico, but tar balls and other debris from the spill are threatening the region’s shoreline.

BP’s latest attempted fix hit a snag yesterday when a diamond-tipped saw got lodged in the deepsea pipe through which oil is gushing into the Gulf.

The company freed the cutting tool after several hours of tricky manoeuvring of its robot submarines, paving the way for the process to continue, a source familiar with the work told Reuters.

Toxic substances from the spill have crept to within ten miles of Florida’s northwest panhandle, where officials said it could make landfall by Friday.

The BP oil spill, which began in April, is causing an ecological and economic catastrophe along the US Gulf Coast.

In early European trading on Thursday, BP shares rose 4.2%.

Shares have fallen dramatically since the accident began in April and stabilised on Wednesday after sharp declines in London and Wall Street on Tuesday.