Senate Democrats are seeking to put more pressure on Republicans after a weekend of sporadic negotiations left leaders stalemated in talks to reopen the government and raise the debt limit.

Democrats have decided to ratchet up pressure on Senate Republican Leader Mitch McConnell (Ky.) instead of accepting a deal that locks in automatic spending cuts known as sequestration and reforms to ObamaCare.

Democratic leaders have instead urged Republicans to support a clean bill to raise the debt limit and warned the stock market could plunge on Monday or Tuesday.

Senate Majority Leader Harry Reid (D-Nev.) and McConnell did little direct negotiating on Sunday. The two leaders spoke by phone for about five or six minutes, according to a source familiar with the call.

Reid characterized the conversation as substantive and said he was optimistic about the chances for a deal.