Even though Silicon Valley has had an often-contentious relationship with the US government's national security organizations, it's now time to be neighbors, one top official said Tuesday.

US Homeland Security Secretary Jeh Johnson announced that his office is "finalizing plans to open up a satellite office in Silicon Valley, to serve as another point of contact with our friends here."

Speaking at the RSA 2015 conference on cybersecurity in San Francisco, Johnson said, "We want to strengthen critical relationships in Silicon Valley and ensure that the government and the private sector benefit from each other's research and development."

He added that "cybersecurity must be a partnership between government and the private sector. We need each other, and we must work together."

The tech industry has sought to keep its distance from the US administration over the past two years, since leaked documents from former contractor Edward Snowden suggested intelligence services had special access to data from major Internet companies.

The tech sector has argued that it provides data for lawful requests but does not allow "backdoor" access to the National Security Agency or other government agencies.

More recently, efforts by Apple and Google to encrypt their smartphones without holding access to "keys" has raised concerns in Washington that the moves would make it more difficult to catch criminals and terrorists.

Johnson, whose agency oversees the Secret Service and Transportation Security Administration among others, on Tuesday added his voice to the debate, echoing concerns made by the FBI and NSA chiefs.

"The current course we are on, toward deeper and deeper encryption in response to the demands of the marketplace, is one that presents real challenges for those in law enforcement and national security," he said.

"Our inability to access encrypted information poses public safety challenges. In fact, encryption is making it harder for your government to find criminal activity, and potential terrorist activity."

Johnson told the industry gathering that "we need your help to find the solution" and called for "a balance between the basic, physical security of the American people and the liberties and freedoms we cherish as Americans."

The DHS chief said another reason for the Silicon Valley office is to help recruit people with technology skills to work for the government.

"We want to convince some of the talented workforce here in Silicon Valley to come to Washington," he said.

He added that a new program called the United States Digital Service "provides the option for talent to flow and rotate" between government and the private sector.

"This will build capacity on all fronts. I hope some of you listening will consider a tour of service for your country."