The administrative subpoenas that were served to two travel bloggers, Steve Frischling and Chris Elliott, on Thursday - for disclosing the identity of the source that 'leaked' to them the Transportation Security Administration (TSA)'s new airline security directive that they posted online - have been dropped.

The two bloggers were being interrogated by the TSA's special agents about the security directive which outlined new screening measures that became effective from December 25 - the day when a 23-year-old Nigerian man, Umar Farouk Abdulmutallab, attempted to bomb an Amsterdam-Detroit flight of Northwest Airlines.

As per the TSA, since the security directive was not was for public disclosure, the bloggers were asked to reveal the details of the source which passed on the document to them, which both of them subsequently posted online within minutes of each other.

It is for the second time within a month that a sensitive airline security document of the TSA has made its way to the Internet. President Barack Obama has ordered a review of the US aviation security, along with the review of the intelligence information that the government had about Abdulmutallab and the reasons for not sharing the information with the concerned agencies.

Meanwhile, about the withdrawal of the subpoenas served to the bloggers, the TSA elucidated that the investigation into the close-call attack was "nearing a successful conclusion, and the subpoenas are no longer in effect."