WASHINGTON - There was a time when the top Republican and Democratic leaders in Congress used to be at least frenemies, sparring over all sorts of policy issues, but keeping their salty language mostly behind closed doors.

But as House Speaker John Boehner and Senate Majority Leader Harry Reid have traded barbs during the first week of the government shutdown, it's become clear that the two have come to detest each other.

The loathing has spilled over into television interviews, on the pages of newspapers and in statements from each of their offices.

Reid, a former boxer known for his bare-knuckle tactics, has been the more vocal of the two. The latest volley came as Reid challenged Boehner to hold votes on the clean continuing resolution, a measure the Republican leader said could not pass the House.

Getty Images

"Why are you afraid? Are you afraid this measure will pass, the government will reopen and Americans will realize you took the country hostage for no apparent reason? Why is the speaker opposed to these reasonable solutions?" Reid said Monday on the Senate floor.

Earlier in the day, the Nevada Democrat's spokesman questioned Boehner's credibility.

"Speaker Boehner has a credibility problem," Reid aide Adam Jentleson said. "From refusing to let the House vote on a bill that was his idea in the first place, to decrying health-care subsidies for members of Congress and staff that he worked for months to preserve, to stating that the House doesn't have the votes to pass a clean CR at current spending levels, there is now a consistent pattern of Speaker Boehner saying things that fly in the face of the facts or stand at odds with his past actions.

"Americans across the country are suffering because Speaker Boehner refuses to come to grips with reality," Jentleson added.

Within a couple of hours, Team Boehner shot back: "It's time for some Washington Democrats to step up, act like an adult, and start talking about how we reopen the government, provide fairness for the American people under ObamaCare, and deal with the drivers of our debt and deficits," Boehner spokesman Michael Steel said in a rebuttal to Jentleson.

And Boehener's top spokesman didn't stop there.

"Passing a spending bill at the level required by law isn't a 'concession' - so it's time for Senate Democrats to stow their faux outrage and deal with the problems at hand. The federal government is shut down because Democrats refuse to negotiate, and the debt limit is right around the corner," Steel added.

Privately, Reid has been fuming, labeling Boehner a "coward" in a closed meeting with Democrats last week.

And although Boehner has been more disciplined when it comes to name calling, tensions have been running high between the two for a while. "Go f- yourself," Boehner reportedly told Reid as he passed him in the halls of Congress after the fiscal cliff standoff of 2012.