WASHINGTON – North Korea's massive but poorly trained and equipped military could cause significant damage in the early stages of an attack on its southern neighbor.

But any attack would ultimately be repulsed by superior U.S. and South Korean forces, military analysts say.

It's unclear how serious North Korea is on following through on its threats, but North Korea has increased its bellicose rhetoric recently, renewing worries that its unpredictable leader, Kim Jong Un, could take actions that might trigger a wider conflict.

The North Korean leader said his rockets were ready "to settle accounts with the U.S."

The United States has responded to the heated rhetoric by announcing it flew two B-2 bombers on a training mission over South Korea. It was part of an annual joint-training operation that continues until the end of April.

Analysts say the recent rhetoric is particularly worrisome when coupled with recent provocative actions taken by the North.

In 2010, the North Koreans sank a South Korean warship, killing 46, and launched an artillery barrage on an island that killed two of its civilians and two South Korean marines.

"It's the rhetoric plus the provocations that are increasing the level of tensions," said Steven Kim, an analyst at the Asia-Pacific Center for Security Studies based in Honolulu.

To an extent, the threats are par for the course, said Richard Bush, senior fellow and director of the Center for Northeast Asian Policy Studies at the Brookings Institution. North Korean leaders portray the training exercise as a prelude to invasion, Bush said.

They make provocative statements, occasionally backed up by attacks, and claim to have repelled the West. Bush rated as low the chances of all-out war.

"A lot of it is show for the domestic audience," Bush said. "The North Korean leadership is cynical. They know these are exercises. It's useful domestically. They get their own people spun up. In worrying about war, maybe that distracts from how hungry they are."

Analysts say North Korea's aging military would not be able to prevail in an attack against its southern neighbor.

"This is a military that if you ran them against the Iraqi military in 1991, North Korea would lose," said Jennifer Lind, a professor at Dartmouth College.

But North Korean forces are arrayed along the demilitarized zone with 10,000 artillery pieces capable of reaching Seoul, said Bruce Klingner, a former CIA analyst now at the Heritage Foundation.

That proximity would let them cause a lot of casualties and damage in the initial stages of an attack. The North Koreans have about 1.1 million troops in their armed forces. Three-quarters of them are staged within 60 miles of the DMZ, Klingner said.

They also have long-range missiles capable of reaching targets in Japan and U.S. bases in Guam, Okinawa and the Japanese mainland.

Any conventional attack from the North would likely begin with an artillery barrage, which could include chemical weapons. The North Koreans have 5,000 tons of chemical warheads, Klingner said.

"They would try to overwhelm U.S. and Korean forces with volume," he said.

The artillery barrage would probably be followed by a blitzkrieg of tanks. The North has at least 4,000 tanks, though most of them are older Soviet-era models. Mechanized forces and infantry could also pour across the border. The North's special forces could infiltrate south in advance of an assault.

U.S. warplanes would attempt to destroy the artillery and tanks quickly in precision airstrikes, said Michael O'Hanlon, a military analyst at the Brookings Institution. The worst case: a nuclear missile or aircraft carrying such a weapon could slip through the South's defenses.

Any initial assault would face about 28,500 U.S. troops and about 600,000 troops in the South Korean armed forces.

"In the war game simulations eventually we prevail, but it's World War I (levels of) casualties," Klingner said.

China, however, has an interest in reducing tension, Bush said. Chinese leaders were not pleased to have a U.S. aircraft carrier near its shores after the 2010 incidents. Nor does China want a refugee crisis on its southern border, a likely prospect if war breaks out or the government in the North unravels.

Chinese leverage with North Korea includes shutting off the flow of luxury goods that the North's leaders consider the "coin of the realm," Bush said.