Officials say the conditions of the Potomac River are complicating recovery efforts of the bodies of the 67 presumed dead in a mid-air collision between American Airlines flight 5342 from Wichita and a military Black Hawk helicopter.

The bodies of three soldiers who were on board a military helicopter that crashed into a passenger plane near Washington, D.C. Wednesday night have been recovered, one day after the deadliest U.S. aviation disaster since 2001.

We are now at the point where we are switching from a rescue operation to a recovery operation,” said John Donnelly, the fire chief in the nation’s capital.