Presumed militants of the Niger Delta Avengers struck four pipelines in three days, halting production at key facilities. On May 25, militants blew up a pipeline at Chevron's Escravos facility in Delya state, shutting down all the company's onshore activities in the Niger Delta. The following day, militants hit a Nigerian National Petroleum Corporation (NNPC) pipeline at the Batan oil-field in Warri, Delta state. The day after that, pipelines operated by Shell and Agip in neighboring Bayelsa state were blown up. The NDA had days earlier warned Chevron that no repairs should be carried out on facilities previously targeted by the group, until their demands are fully met. NDA claimed on its official website May 11 that it suspected Chevron was preparing to carry out repair works at the Okan Valve platform, which was blown up by the group at the start of the month. Among its demands, NDA wants to "free the people of the Niger Delta from environmental pollution, slavery and oppression," according to a statement on the group's site. A May 31 deadline had been set for oil companies to quit the Niger Delta. (This Day, May 29; AP, Punch, Nigeria, May 28; Channels Television, Nigeria, Chemical Engineer, May 27; RigZone, May 26; Sahara Reports, May 25)