The latest Pentagon report on China's military rise stresses the importance of expanded and sustained Sino-US military ties yet warns Beijing is seeking to use them to exploit 'vulnerabilities' and weaken US alliances. China's expanding military operations and capabilities as well as periods of 'friction and turbulence' highlight the importance of ties to the broader relationship, says a new chapter of the report, which is delivered annually to the US Congress. Despite commitments from senior political and military leaders, including President Hu Jintao , 'a sustained exchange programme has been difficult to achieve', it notes. 'The result is an on-again/off-again military relationship that limits the ability of the two armed forces to explore areas of co-operation ... improved communications, and reduce the risk that misapprehension or miscalculation could lead to crisis or conflict,' the report says. Its publication comes amid signs of worsening tensions. Beijing again shelved military exchanges earlier this year as the administration of US President Barack Obama approved its first arms sales to Taiwan - friction that has worsened with Washington raising its concerns over the disputed South China Sea and Hu delaying a planned visit to Washington. The report couches the potential future relationship in terms of finding shared interests rather than obvious differences - and moving them beyond 'inevitable' spells of political turbulence. It also repeatedly quotes Obama on the importance of the Sino-US relationship and that the two countries were not 'pre-destined to be adversaries'. It stresses the need for mutually agreed rules of the road at sea to avoid future incidents and lists ongoing anti-piracy work and search and rescue as areas of potential co-operation. 'While China has repeatedly stated its desire for improved US-China military-to-military relations, it has repeatedly sublimated this goal to others it perceives as more important,' the report says. 'Only when China determines that it is in its own interest to sustain engagement through periods of turbulence will it be possible to build a more solid foundation for military-to-military relations.' Intriguingly, while the report highlights the need for ties it details, without commentary, 'benefits China expects to gain'. Apparently suggesting political and intelligence operations, it states that the PLA would be seeking insights on US intentions and capabilities and 'to gain insights into potential US vulnerabilities' as well as US ties with other nations of interest to Beijing. 'Senior political leaders in Beijing also pursue contacts with the Department of Defence to elevate China's status as a regional and world power,' it says. 'In this context, China's leaders seek to use 'normal' defence relations with the United States ... to drive a wedge between the United States, its allies, and its partners, including Taiwan.' Regional diplomats digesting the report yesterday said the references appeared to be a veiled warning to the US Congress to keep a close watch on the management of future ties, which it is mandated to monitor. 'In a section devoted to the importance of the relationship, it stands out as a red flag,' one Asian diplomat said. 'The US wants ties, but not at any cost ... it is now going into this relationship with both eyes wide open.'