BP ratcheted up the rhetoric around multi-billion dollar claims from the Gulf oil spill by warning it would "vigorously" contest lawsuits over one of the world's worst environmental disasters.

While reiterating BP's "bias for settling" at hearings scheduled later this month, CEO Bob Dudley said he would only do so "on fair and reasonable terms."

As he unveiled higher fourth quarter profit on Tuesday and a rise in the dividend, which he said showed BP was putting the spill behind it, Dudley acknowledged the lawsuits were the biggest uncertainty facing the British oil major.

BP Plc has not yet applied for permission to drill its first new Gulf of Mexico oil well since the 4 million-barrel Macondo spill a year ago, the oil major said on Tuesday, although it received permission this month to plug an old well.

The London-based company said it hoped to restart drilling by the end of the year, but added it was still working to improve drilling procedures before making applications.

"We are making sure we have our standards in place for us to go forward," Chief Executive Bob Dudley told analysts Tuesday on a conference call.

BP Plc's $85 million settlement with the U.S.

Differences between rich and developing countries prevented G20 finance ministers from agreeing measures on Saturday to curb global warming, casting more doubt on U.N. efforts to agree a new climate treaty.

OPEC said oil was not to blame for climate change and consuming countries should pay to fight the threat, while the CEO of Royal Dutch Shell said drivers could help by not buying Hummer sports utility vehicles.

"Oil is not responsible," the producer group's Secretary General, Abdullah al-Badri, told reporters on Thursday on the sidelines of the International Oil Summit in Paris.