Senator Charles Schumer says retailers that sell assault weapons should stop offering them for purchase while congress discusses gun regulation legislation.

On Sunday, the senator released a letter he sent to major retailers asking for a voluntary moratorium. Schumer says consumer demand for guns has gone up in the weeks since the December mass shooting in Newtown, Conn.

He says congress is debating the issue, and if measures get passed that limit these type of weapons, it won't help if more of them have recently been sold.

President Barack Obama has made gun control a top priority. Vice President Joe Biden is expected to give him a comprehensive package of recommendations for curbing gun violence this week.