LONDON — Eric Schmidt, the executive chairman of one of the world’s biggest technology companies, has arrived in North Korea, a nation where the use of the Internet is highly restricted.

Google’s Schmidt is visiting the East Asia nation with former New Mexico Gov. Bill Richardson.

Speaking in Beijing ahead of the flight to Pyongyang, Richardson described the visit as “a private humanitarian mission.” The former governor, who has visited North Korea several times over the past 20 years, is expected to try to discuss the case of a U.S. citizen jailed in the country.

But Schmidt’s participation in the trip is seen as more controversial and he has drawn criticism from some quarters, including the U.S. State Department, because the visit comes only weeks after North Korea launched a long-range rocket. The visit has also prompted speculation about what the businessman hopes to accomplish in the reclusive nation.

“We don’t think the timing of the visit is helpful, and they are well aware of our views,” State Department spokeswoman Victoria Nuland told reporters last week.

In Beijing, Richardson said, “This is not a Google trip, but I’m sure he’s [Schmidt] interested in some of the economic issues there, the social media aspect. So this is why we are teamed up on this.”

Jared Cohen, director of Google Ideas, is also on the trip.