More documents from the Edward Snowden leak show that the National Security Agency has tapped Google and Yahoo's cloud networks to access massive amounts of data, including from Americans.

The report released Wednesday by The Washington Post indicates that the NSA has gained access to the fiber optic connections between the servers that power each company's network.

According to a top secret accounting dated Jan. 9, 2013, NSA’s acquisitions directorate sends millions of records every day from Yahoo and Google internal networks to data warehouses at the agency’s Fort Meade headquarters. In the preceding 30 days, the report said, field collectors had processed and sent back 181,280,466 new records — ranging from “metadata,” which would indicate who sent or received e-mails and when, to content such as text, audio and video.

When you send email or store files with an internet company, that data is regularly shared among servers around the world, in order to ensure quick access to your information from wherever you happen to be. Google and Yahoo run customized private networks to shuttle that information around, passing between and within countries, as the Post indicates in a graphic. To move that information, the companies use fiber optic connections, light-speed networks running over thin glass cables. According to the Post, it's those connections that the NSA is able to monitor. None of Yahoo's inter-server traffic is encrypted. Not all of Google's are either, prompting a little smiley face in a slide obtained by the Post.

SSL is "secure socket layering," the encryption tool used to protect traffic as it moves over the internet and which is hard for the NSA to read. Once it gets to Google's servers, though, that SSL is removed. 

"Tapping the Google and Yahoo clouds," the Post writes, "allows the NSA to intercept communications in real time and to take 'a retrospective look at target activity,' according to one internal NSA document." By shunting millions of records to their Maryland servers each month, the NSA can more fully flesh out its social portraits of users. Included in that transmission of data is the activity of Americans, though it's not clear how and when that activity is stored.

NSA head Keith Alexander, speaking at a conference on Wednesday, responded to reporters' questions with careful denials.

The accusation, of course, isn't of compromised servers; rather, it's the networks between those machines. The Post points out that company staffers were surprised and angry to hear about the compromising of their networks.

Two engineers with close ties to Google exploded in profanity when they saw the drawing [above]. “I hope you publish this,” one of them said.

Update, 5:30 p.m.: Google released a statement on the new revelations, via The Guardian.

"We do not provide any government, including the US government, with access to our systems. We are outraged at the lengths to which the government seems to have gone to intercept data from our private fiber networks, and it underscores the need for urgent reform."

Pictured: The two faces of the NSA. At right, Alexander.