Occidental Petroleum on Thursday sought to scuttle the proposed deal, submitting a higher, $38 billion cash-and-stock offer for Anadarko. Anadarko's board said on Thursday it would evaluate the new proposal.

"I'll just remind everyone that we've got a signed deal that has been approved by both boards and we've moving forward with integration planning," said Chevron Chief Executive Michael Wirth on a conference call with analysts. He said a "sizeable" group of employees had already met.

Wirth declined to say whether Chevron would raise its offer in light of Occidental's higher bid. Chevron has the ability revise the structure of its 75 percent stock, 25 percent cash bid, Chevron finance chief Pierre Breber said on the same call. "We could put more cash in if that's what Anadarko wanted to do," he said.

(Reporting by Gary McWilliams; Editing by James Dalgleish)