Washington (CNN)This week more than 400 Chinese officials are descending on Washington for three days of political, security and economic talks.

The countries top diplomats and finance officials are gathering for the annual U.S.-China strategic and economic dialogue, viewed as an important forum managing ties between the world’s two leading economies.

The breadth of the talks, now entering their seventh year, reflects efforts to deepen and strengthen ties between the global powers.

But this year’s dialogue is clouded by mistrust and heightened tensions over China’s assertiveness in the South China Sea and suspicions Beijing was behind a massive hack on U.S. government computers in which millions of personnel files were stolen.

Deputy Secretary of State Antony Blinken and China’s executive vice foreign minister, Zhang Yesui, led talks between civilian and military officials on Monday to discuss security issues.

On Monday night, U.S. Secretary of State John Kerry and Treasury Secretary Jack Lew are hosting China’s State Councilor Yang Jiechi and Vice Premier Wang Yang for a private dinner, before the two days of talks of political and economic talks officially kick off on Tuesday.

A senior State Department official briefing reporters said Monday’s discussions were already “candid and to the point” and that the aim of the security discussions was to “really try to get at those issues which are the most likely to drive strategic mistrust between the U.S. and China.”

“The talks are all the more important for the need to address these issues head on, not try to paper them over, not try to agree to disagree,” the official said. “But to try to actually talk about them, and see if we can in particular kind of try to narrow the differences but certainly at least make sure that we’re communicating clearly on the areas of difference so that we don’t miscalculate, misunderstand, etc.”

Both sides are emphasizing areas of cooperation between the two countries, like diplomacy on North Korea and a nuclear deal with Iran, climate change, Afghanistan and fighting the Ebola virus.

“We have agreed with the Chinese that we are going to try to expand those areas where our interests overlap and expand cooperation in those areas,” the senior State Department official said.

But the official insisted the discussions will be “candid and to the point” and they will not “paper over” differences related to the South China Sea and cybersecurity.

“What we’re trying to do is to show that we can effectively manage areas of ongoing differences and work to narrow those differences over time,” the official said.

Danny Russel, the top U.S. diplomat for Asia, set the scene for the talks on Thursday, saying a direct approach was best.

“We don’t turn a blind eye to problems. We discuss them and we seek to tackle them directly,” he said. “We don’t always see eye-to-eye but the fact is global challenges require that we cooperate.”

The scale of Chinese building and militarization of man-made islands in the South China Sea has raised concern in the region about Beijing’s territorial ambitions.

Last month the U.S. flew a rare and highly publicized military surveillance flight in the area to highlight the massive scale of activity. China calls the islands its sovereign territory, but the U.S. has said China is building in disputed waters and is threatening freedom of navigation in sea lanes which are key for international trade.

Russel called last week’s announcement by China that it planned to continue and expand construction on reclaimed outposts “troubling.”

“Neither that statement, nor that behavior, contributes to reducing tensions,” Russel said. “We consistently urge China to cease reclamation to not construct further facilities and certainly not to further it.”

The already tense relationship between the U.S. and China over cybersecurity has recently become more fraught after the Chinese suspended a separate track of talks to discuss the issue a year ago when the U.S. charged five Chinese military officers with hacking. Although the cyber working group has not met since, Russel and other U.S. officials have said cybersecurity would be raised throughout the talks, both from a security context and an economic one.

“Certainly the issue will be addressed in pretty direct terms with the Chinese,” the senior State Department official said Monday.

The talks area as much about U.S.-China financial ties as political ones, and take place against the backdrop of China’s growing economic influence across Asia. Questions about U.S. economic leadership in the region come on the heels of Congress’ rejection of fast-track trade authority for President Barack Obama’s landmark Asia-Pacific trade deal.

Progress toward a bilateral investment treaty between the two countries has also been slow.

Both sides have an interest in reducing tensions ahead of Chinese President Xi Jinping’s visit to the White House in December, his first since taking office two years ago.

China’s state-run Xinhua news agency on Friday quoted the foreign ministry spokesman as saying talks are an opportunity to “push for a new model of major power relationship.”

The Chinese story said climate change would be a “hot topic” at the upcoming dialogue, but did not mention cybersecurity or the South China Sea.

By Elise Labott June 22 2015 in CNN