An apparatus for occluding a venous or arterial puncture site is disclosed including a plug insertable within, or adjacent to, a puncture site in a wall of a body lumen. An insert is forced into an aperture within the plug to cause expansion thereof. The insert may be drawn into the aperture by applying tension to a line passing therethrough and secured to the insert. Barbs may secure to the plug to engage the wall of the body lumen or adjacent tissue tract. Elongate members passing through the wall of the plug may be forced outwardly into the wall of the body lumen or adjacent tissue as the insert is forced into the aperture.