Only four Port Authority officials met this week's deadline to turn over all documents subpoenaed in the New Jersey Legislature's investigation into the George Washington Bridge lane closures, according to a list provided to NBC News.

Fourteen others who were subpoenaed-- including officials in Gov. Chris Christie's office, members of his campaign committee, his press secretary and other top aides-- have either been granted extensions or have begun turning over material "on a rolling basis," according to a source close to the investigation.

Two of those subpoenaed -- former Deputy Chief of Staff Bridget Kelly and former campaign manager Bill Stepien -- have invoked their Fifth Amendment right against self incrimination and declined to turn over any material.

The list of those who have yet to fully comply with the subpoenas includes David Sampson, Christies' close political ally who chairs the Port Authority; Charles McKenna, Christie's former chief counsel; Kevin O'Dowd, Christie's former chief of staff and nominee to be attorney general; Reginia Egea, Christie's incoming chief of staff; and Nicole Davidman Drewniak, a Christie fundraiser and wife of Christie press secretary Michael Drewniak.

Christie, in remarks during a call-in radio show on Monday, said he office was producing documents in response to the subpoenas.

"We, the Governor's Office, has started to produce things today,” he said. “We did not ask for an extension. We started to produce documents today but we’re doing so on a rolling basis. We’re working as hard as we can to get through because there was a lot of stuff asked for from us.”

All told, the special legislative committee investigating whether the bridge lane closures in September 2013 were politically motivated has issued 20 subpoenas to members of the Christie administration, his campaign and officials of the Port Authority, which oversees the bridge. The four Port Authority officials who have complied with the subpoena were William Baroni Jr., the former deputy executive director who resigned his post in December; Chief Administrative Officer Cristina Lado, Paul Nunziato, president of the Port Authority Police Benevolent Association, and spokesman Philippe Danielides.

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The subpoenas from the legislative committee are separate from those issued by the U.S. Attorney’s Office in Newark, N.J., which also is investigating the bridge lane closures. Christie confirmed Monday night that his office had been served with a subpoena from the U.S. Attorney’s Office, along with his campaign committee and the New Jersey Republican Party.

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