Citing fears of terrorism on Capitol Hill, Sen. Mark Dayton (D-Minn.) has closed his Washington office until after the Nov. 2 elections.

In a statement, Dayton said Senate Majority Leader Bill Frist (R-Tenn.) recently presented a top-secret report on national security that prompted Dayton to shutter his office in the Russell Building and have some staff go to Minnesota with others trying to work out of unidentified office space in Washington. Dayton said he could not reveal the details of the report.

“I do so out of extreme, but necessary, precaution to protect the lives and safety of my Senate staff and my Minnesota constituents, who might otherwise visit my office in the next few weeks,” Dayton said of the closure. “I feel compelled to do so, because I will not be here in Washington to share in what I consider to be an unacceptably greater risk to their safety.”

Dayton said he was “dismayed” with Frist for rejecting, after three one-on-one discussions with Dayton, a request to convene a meeting of all 100 Senators to discuss the security situation on the Hill. “I am dismayed, and perplexed, by his unwillingness to meet with us further about the information, which he initially brought to our attention. In the absence of that further discussion, I have made my own decision about my office, as is my responsibility.”

Amy Call, spokeswoman for Frist, stressed that no new information had been received since the Capitol went to a higher security alert in August and that the Majority Leader felt no need to close down his office.

“At this point we are sticking with the security plans in place,” Call said. “He feels that our office will remain open and continue to work with the Sergeant-at-Arms and the Capitol Police to maintain the safety of everyone.”

Dayton is believed to be the only Member of Congress to close his or her office for security concerns.