PHNOM PENH, Cambodia (AP) — Cambodia and China on Wednesday held their first meeting of what is called a “2+2” Strategic Dialogue Mechanism, bringing together both countries’ foreign and defense ministers to deepen mutual political and security ties.

Chinese Foreign Minister Wang Yi and Defense Minister Dong Jun are visiting Cambodia to hold talks with their counterparts, Foreign Minister Prak Sokhonn and Defense Minister Tea Seiha.

These talks are an initiative proposed by Chinese President Xi Jinping during his state visit in April last year, aimed at boosting relations and the comprehensive strategic partnership between the two nations. China has worked to increase its sphere of influence in Southeast Asia, and initiated the ministerial-level “2+2” dialogue format with Indonesia last year.

The Chinese Foreign Ministry announced Tuesday that Wang Yi will also visit Thailand and Myanmar following his stop in Cambodia.

While in Cambodia, both Chinese ministers are also to hold separate meetings with Senate President Hun Sen and Prime Minister Hun Manet. Following the joint “2+2” meeting, Wang Yi on Thursday is scheduled to have in-depth discussions with Prak Sokhonn to discuss the implementation of existing cooperation frameworks and contributions to regional peace, security and stability.

No details of any of the meetings were immediately available from Cambodian officials.

China is the largest investor and aid donor for Cambodia, which stands as Beijing’s closest political partner in Southeast Asia. Their bilateral trade reached $19.73 billion last year, overwhelmingly in China’s favor.

The close relations fuel suspicions among analysts and the U.S. government that a Chinese-funded project to upgrade Cambodia’s Ream Naval Base will be used as a strategic military outpost by China. Construction at the base, located on the Gulf of Thailand, last year saw the completion of a new pier to accommodate larger ships, a dry dock for repairs and other features.

Washington has publicly expressed the concern that Beijing has been secretly granted exclusive privileges to use the base, though Cambodian officials have repeatedly denied the accusations. At the opening of the base expansion in April last year, Prime Minister Hun Manet specifically denied these allegations, declaring that the expansion wasn't hidden from other countries.

Three months ago, the USS Cincinnati, with a crew of about 100, became the first U.S. Navy warship to dock at the facility since its Chinese-funded renovation was completed.