The Libyan government and a rebel group stepped up rhetoric Wednesday as Tripoli responded to a vow by dissidents to sell oil with a threat to sink their cargoes. The exchange, which comes after Libya shot at a tanker it said was illegally entering its waters, raises concerns about whether the chaos that has more than halved oil production in the North African nation and rattled oil markets could get worse. On Sunday, the Libyan Navy stopped a tanker it said was about to load at the blocked Es Sider terminal—though the shipper said it had already renounced entering the oil port. The government has banned shippers from lifting oil at several ports in eastern Libya, including Es Sider, after they fell under the control of a rebel militia seeking autonomy for its region, Cyrenaica. Sunday’s incident and the verbal escalation that followed came as the rebels are making […]