The senators demanded the administration justify the acquisition of land along the Missouri River.
Rubio said Obama should make it clear the U.S. stands with Hong Kong protesters.
"It's clear that our security plan was not properly executed," Julia Pierson said.
Most members are back in their districts campaigning.
They said customers have been "flaunting assault rifles" in "terrifying" displays.
House and Senate Illinois Democratic lawmakers requested an investigation of the Federal Aviation Administration's security procedures at air traffic control facilities following two fires.
Rep. Walter Jones (R-N.C.) on Monday urged Speaker John Boehner (R-Ohio) to schedule a vote to authorize the use of military force in Iraq and Syria following the midterm elections.
Sen. Jack Reed (D-R.I.) applauded President Obama’s decision to extend visas to Liberian immigrants.
House Homeland Security Committee Chairman Michael McCaul (R-Texas) on Monday demanded a review from the Secret Service on its White House security procedures.
GOP control of Congress would mean more gridlock, confrontation and partisanship, Hoyer said.