BEIJING (AP) — Beijing and Pyongyang have agreed to accelerate joint development of two trade zones in North Korea during a visit by leader Kim Jong Un's powerful uncle Jang Song Thaek.

The visit by Jang, a vice chairman of the powerful National Defense Commission, marks one of the highest-level diplomatic exchanges between the North and its most important ally since Kim took over following his father's death last year.

Earlier this month, Kim held talks with Wang Jiarui, head of the Communist Party's international affairs office, in Pyongyang and feted him with a banquet.

The official China Daily newspaper said Wednesday that Jang's six-day trip would also take him to north China's Jilin and Liaoning provinces, close to the North Korean border, and described it as a possible "prelude" to a visit by Kim.

Jang is married to late leader Kim Jong Il's sister, Kim Kyong Hui, and is seen as a leading economic policy official.

On Tuesday, he held talks with Chinese Commerce Minister Chen Deming and the two attended a meeting of the joint committee overseeing development of the two trade zones, an online commerce ministry statement said.

"Both sides agreed that with the mutual effort of government and enterprise from both countries, cooperation in developing the two economic zones has already yielded impressive remarkable results, and has entered the stage of substantive development," it said.

Kim, who has led North Korea since his father's death in December, has promoted younger economists to key party positions as part of a stated push to resuscitate his country's economy. North Korea has lagged far behind the rest of Northeast Asia economically, and much of the nation is impoverished outside the capital Pyongyang.

The ministry said the two sides signed a number of cooperation agreements related to their development of the two special economic zones: Rason on the Korean Peninsula's northern tip and Hwanggumphyong, an island in the Yalu River that marks their border to the southwest.

It said plans for Rason would see it becoming a manufacturing base, logistics center and tourism hub, though the new agreements were still primarily focused on basic infrastructure, such as a plan to transmit electricity directly to the zone overland from China.

The Hwanggumphyong zone will focus on information technology, tourism, agriculture and garment manufacturing, it said.

Rason has recently begun to develop thanks to Chinese infrastructure projects, but Hwanggumphyong has languished since ground was broken last year.

The China Daily said in an editorial Wednesday that Chinese investment in the zones would help North Korea's battered economy and improve stability on the Korean peninsula.

"The DPRK is in urgent need of capital to help revitalize its waning economy," the paper said. "It can be expected that as a result of the agreements, Chinese investment in the special economic zones of the DPRK will increase rapidly."

It noted that bilateral trade last year was $5.7 billion, up from $3.5 billion in 2010.