Beijing's top diplomat returned to Hanoi for the second time in four months yesterday as China and Vietnam sought to reset ties following a dispute over an oil rig. The one-day visit by State Councillor Yang Jiechi is seen as a move to prepare for next week's Asia-Pacific Economic Cooperation forum in Beijing, which Vietnamese President Truong Tan Sang is expected to attend. Yang was in Hanoi for the seventh meeting of the Vietnam-China Steering Committee for Bilateral Cooperation, a supposedly annual event for the two countries to discuss cooperation. During the meeting, Yang told Vietnamese Deputy Prime Minister Pham Binh Minh, who headed the Vietnamese delegation, that relations had resumed "step by step", according to the Vietnamese foreign ministry. "The two sides should … properly handle and control maritime disagreements, creating a favourable environment for bilateral cooperation," the ministry quoted him as saying. The neighbours agreed to resolve maritime territorial disputes "in an appropriate manner" and promote negotiation mechanisms, the Chinese foreign ministry said on its website. Relations between the communist allies nosedived in May after China deployed an oil rig in waters off Vietnam's coast claimed by both countries. Yang visited Hanoi for a one-day meeting at the height of tensions in mid-June. Chinese media described the event as a "leaders' meeting" of the Vietnam-China Steering Committee for Bilateral Cooperation. But a source close to Vietnam's foreign ministry and a Chinese scholar said it was an ad-hoc occasion created for both countries to address the oil rig crisis. China then withdrew the rig on July 16, a month earlier than planned. Yesterday the two sides agreed to accelerate joint surveys off the Gulf of Tonkin and "quickly establish" a working group on infrastructure and a working group on currency. Yang's visit also appeared to be part of positive moves by Beijing ahead of the Apec summit, said Carl Thayer, a South China Sea expert from the Australian Defence Force Academy. "This [visit] means they will reset relations. Instead of hyping the South China Sea [disputes], both of them will hype cooperation and trade," said Thayer. Zhang Mingliang , an expert on Southeast Asia at Jinan University in Guangzhou, said Yang's visit could pave the way for a meeting between President Xi Jinping and Sang on the summit's sidelines. "Due to mistrust and the maritime disputes, it's impossible for the two countries to ever become as close as they claimed to be," he said. "But it's possible that we could return to the level before the oil rig incident, when … high-level exchanges were regular."