Intelligence services are finding it harder to recruit staff since the pandemic as prospects want to work from home and would rather not part with their personal cell phones, the head of Germany's foreign intelligence service BND said on Monday.

"We cannot offer certain conditions that are taken for granted today," said Bruno Kahl, who described finding enough and the right staff as a great challenge as baby boomers are heading into retirement.

"Remote work is barely possible at the BND for security reasons, and not being able to take your cell phone to work is asking much from young people looking for a job," he added.

Some 6,500 people work for the BND, according to its homepage.