A U.S. special envoy called Saturday for talks with North Korea and urged Pyongyang not to launch a missile and stop issuing threats to its southern neighbor.

North Korea escalated tensions Thursday by warning it could not guarantee the safety of South Korea's passenger jets flying near its airspace if annual joint U.S.-South Korean military maneuvers went ahead as planned Monday.

"We're reaching out now. We want dialogue," Stephen W. Bosworth told reporters upon arrival in South Korea, the last leg of a regional tour that took him to China and Japan.

The U.S. has not held official talks with North Korea since President Barack Obama took office earlier this year as his administration formulates its North Korea policy.

Some analysts say the communist country is trying to grab Obama's attention with the threat of a missile launch, speculation dismissed by North Korea.

Obama's envoy on North Korea also urged Pyongyang to halt its belligerent tone toward its southern neighbor after issuing the warning about the safety of commercial airlines.

"I don't think the warning was very helpful," said Bosworth. "Everyone would be much happier if they would drop that line of rhetoric."

The comments came amid heightened tensions over stalled reconciliation efforts on the divided Korean peninsula.

Bosworth also said the North's expected launch of a missile or satellite was "very ill-advised."

Pyongyang has said it was preparing to send a communications satellite into space, but regional powers suspect the claim is a cover for the launch of a long-range missile capable of reaching Alaska.

In Beijing, Chinese Foreign Minister Yang Jiechi shied away from directly criticizing China's neighbor and longtime communist ally over the threatened rocket launch but called for a toning down of regional tensions.

"We believe that safeguarding peace and stability on the Korean peninsula serves the interests of all relevant parties," Yang said at a news conference.

Bosworth met Russia's nuclear envoy in Seoul but he declined to elaborate. He also plans to hold consultations with South Korean officials on Monday before returning home.

The joint U.S.-South Korean military exercises begin Monday and are scheduled to run 12 days. Washington and Seoul say the exercises are defensive, not preparation for an invasion as North Korea claims.

The U.S. military said it would go ahead with the drills involving its 26,000 military personnel in South Korea, an unspecified number of southern soldiers and a U.S. aircraft carrier.

The exercises are a "grave military provocation that greatly threatens peace and stability on the Korean peninsula," the North's main Rodong Sinmun newspaper said in a commentary carried by the country's official Korean Central News Agency.

The two Koreas technically remain at war because their 1950-53 war ended in a cease-fire rather than a peace treaty.