Ted Stevens: Longest-serving Republican senator in history

FBI and Internal revenue Service agents entered the house to investigate Sen Stevens's ties to the jailed head of an oil service company, Bill Allen.

Mr Allen was sentenced this year after admitting to bribing state legislators.

Sen Stevens, 83, who is up for re-election next year, has not been charged with any wrongdoing.

He is being investigated for his links to Mr Allen, who was the chief executive of Veco, the biggest oil service company in Alaska.

In May, Mr Allen and another Veco executive Rick Smith pleaded guilty to several corruption charges, including paying more than $400,000 to bribe Alaskan legislators.

Investigators searched inside and outside the house

Contractors have told a federal grand jury that Mr Allen oversaw a project that doubled the size of Sen Stevens's home in the Alaskan ski resort of Girdwood.

Sen Stevens has said that money for the remodelling of his house came out of his own pocket.

Sen Stevens, who has been in office since 1968 and an influential member of Congress for many years, said he would not comment on the search.

"I continue to believe this investigation should proceed to its conclusion without any appearance that I have attempted to influence its outcome," he said in a statement.