Senior U.S. and Chinese diplomats are set to meet Sunday at a time of rising tensions between Washington and Beijing.

The U.S. State Department said Wednesday that Deputy Secretary of State Wendy Sherman, the No. 2 American diplomat, will meet with Foreign Minister Wang Yi and others in Tianjin, China, as part of an Asia trip which includes stops in Japan, South Korea and Mongolia as well as Oman.

FILE - State Department spokesperson Ned Price speaks during a media briefing at the State Department, July 7, 2021.

"In the context of relationships that are complex, that are challenging, that are dynamic, we believe it's important to maintain open lines of communication between high-level officials. And that includes in times of, as in the case with the PRC (People's Republic of China), sustained competition," said State Department spokesperson Ned Price during a briefing on Wednesday.

Sherman's meetings with Chinese officials come as the Biden administration accuses China of instigating a large-scale hack of Microsoft Exchange email server software. On Monday, the U.S. indicted four Chinese nationals on charges they tried to steal U.S. trade secrets, technology and disease research. China rejected the allegations.

Sherman's trip, which is widely seen as a step toward future higher-level meetings between the U.S. and China, comes as Defense Secretary Lloyd Austin visits Singapore, Vietnam and the Philippines.

Austin will be the first official from President Joe Biden's Cabinet to head to Southeast Asia. Sherman's meeting with Wang in Tianjin will be the highest-level direct talks since March's meeting in Alaska between the two nations' top diplomats.

U.S. officials say Beijing's aggressive activities in the South China Sea are high on the agenda. Washington has rejected China's "unlawful" maritime claims in the sea, accusing China of continuing to "coerce and intimidate Southeast Asian coastal states" and threatening freedom of navigation in the critical global waterway.

FILE - Defense Secretary Lloyd Austin speaks during a briefing at the Pentagon in Washington, May 6, 2021.

"I'll emphasize our commitment to the freedom of the seas and also make clear where we stand on some unhelpful and unfounded claims by China in the South China Sea," said Austin on Wednesday at the Pentagon.

"We don't believe that any one country should be able to dictate the rules, or worse yet, throw them over the transom," added the Defense chief.

ASEAN policy and Myanmar

In early August, Brunei is hosting foreign ministers from the Association of Southeast Asian Nations (ASEAN) and the U.S. in a mostly virtual gathering to address issues including regional security.

Addressing a videoconference on the U.S.-ASEAN relationship, senior U.S. officials and American lawmakers renewed a call for the Southeast Asian bloc to work on the restoration of democracy in Myanmar, pressing its military leaders to cease violence and release all those unjustly detained.

Henrietta Levin, the National Security Council director for Southeast Asia and ASEAN affairs, said Washington is calling on ASEAN members "to quickly hold the Burmese military accountable to the ASEAN five-point consensus."

Levin was referring to a statement by ASEAN leaders issued in late April that urged ending the violence as well as establishing political talks and naming a regional special envoy on Myanmar.

FILE - Rep. Steve Chabot speaks at a House subcommittee hearing on Hong Kong, Dec. 2, 2014.

U.S. Representative Steve Chabot, an Ohio Republican who is also the co-chair of the U.S.-Philippine Friendship Caucus in the U.S. Congress, said "fostering relationships" with U.S. allies from the Southeast Asian bloc through "economic engagement" is an effective approach to address challenges posed by China and "its bid for regional and global hegemony."

U.S. Representative Young Kim, a Republican from California, urged American businesses and companies to "hold principles" when operating in Myanmar as people in the country seek to restore the rule of law and democracy.

"I am struck by the continuing violence and abuses" in that country, said Kim.

ASEAN is collectively the third-largest economy in the Indo-Pacific and the fifth-largest economy in the world. The U.S. exports over $122 billion in American-made goods to ASEAN annually.