Reid: Geithner getting more 'solemn' in debt talks

For months, Geithner has expressed optimism that a bipartisan agreement would be reached. Some contend Geithner's public statements have been aimed at soothing an anxious stock market.

Behind closed doors, Geithner's mood is not upbeat, Reid suggested.

"I have watched Secretary Geithner during the course of these discussions become more concerned and solemn each time we meet. He understands, more than any one else [the ramifications of not reaching an agreement.]"

Reid ripped Republicans for walking away from various negotiations, warning that the stock market could "crash" if the debt ceiling is not lifted.