SAN FRANCISCO (AP) – Four U.S. senators want Facebook to make it easier for its more than 400 million users to protect their privacy as the website develops new outlets to share personal information.

The call for simpler privacy controls came in a letter that the senators planned to send Tuesday to Facebook founder Mark Zuckerberg. The Associated Press obtained a draft of the letter signed by Sen. Charles Schumer, D-N.Y.; Sen. Michael Bennet, D-Colo; Sen. Mark Begich, D-Alaska; and Sen. Al Franken, D-Minn.

It marked the second time in three days that Schumer has expressed his misgivings about a series of changes that Facebook announced last week. The new features are designed to unlock more of the data that the online hangout has accumulated about people during its six-year history.

Schumer sent a letter Sunday to the Federal Trade Commission calling for regulators to draw up clearer privacy guidelines for Facebook and other Internet social networks to follow.

In a written response to Schumer, Facebook vice president Elliot Schrage said Tuesday that the company welcomes “a continued dialogue with you and others because we agree that scrutiny over the handling of personal data is needed as Internet users seek a more social and interactive experience.”

He echoed earlier statements that Facebook’s aims to give users more control, not less. Privacy advocates have disagreed, saying the company now expects users to share things publicly that they previously could restrict to a select group of online friends.

The political pressure threatens to deter Facebook’s efforts to put its stamp on more websites, a goal that could yield more moneymaking opportunities for the privately held company.

Among other things, Facebook is plugging into other websites so people can communicate their interests with their online entourages. Facebook also tweaked its own website to create more pages where people’s biographical information could be exposed to a wider audience.

Before personal information can be shared with other websites, the senators want Facebook to seek users’ explicit consent, a process known as “opting in.” Facebook currently can share some personal information with websites unless individual users opt out by telling the company they don’t want those details to be passed along.

The senators also object to Facebook’s decision to allow other businesses store users’ data for more than 24 hours.

Zuckerberg, who turns 26 next month, says he just wants to build more online avenues for people to connect with their friends and family. Some of his previous efforts have been detoured by privacy concerns, most notably in 2007 when Facebook users revolted against notification tool, called Beacon, that broadcast their activities on dozens of websites.

Facebook responded to that rebellion by giving people more control over Beacon before scrapping the program completely.

Copyright 2010 The Associated Press.