Quarrels have broken out behind the scenes of Anthem Inc's proposed acquisition of Cigna Corp, as the health insurers seek regulatory approval for their landmark deal, the Wall Street Journal reported on Sunday. The newspaper said the squabbles could delay or derail antitrust approvals, though the deal does not appear to be in danger of imminent collapse. An Anthem spokeswoman declined to comment on the Journal report. Cigna officials were not immediately available to comment. In a series of letters between top officials including their chief executives, the Journal said Anthem and Cigna accuse each other of violating the July merger agreement and fumbling submissions to regulators. Copyright Reuters, 2016