"We are united in making clear to Beijing our opposition to unilateral changes to the status quo with Taiwan," Blinken said after the G7 foreign ministers' meeting.
"We are also equally committed, individually and collectively, to constructively engaging with Beijing if it chooses to contribute its efforts to address shared global challenges," he said.
The comments come amid concerns of division among G7 nations on Taiwan.
French President Emmanuel Macron visited Beijing earlier this month. He then stirred controversy by suggesting Europe should not follow Washington's lead on Taiwan.
Representatives from the EU, Spain and Germany have also visited Beijing in recent weeks.
G7 foreign ministers address China in joint statement
The G7 foreign ministers issued a joint statement.
It addressed China's activities in the East and South China seas:
"We remind China of the need to abstain from threats, coercion, intimidation, or the use of force. We remain seriously concerned about the situation in the East and South China seas. We strongly oppose any unilateral attempts to change the status quo by force or coercion. There is no legal basis for China's expansive maritime claims in the South China Sea, and we oppose China's militarization activities in the region."
The statement also mentioned Taiwan:
"We reaffirm the importance of peace and stability across the Taiwan Strait as an indispensable element in security and prosperity in the international community, and call for the peaceful resolution of cross-strait issues."
It also discussed China's human rights record:
"We continue to raise our concerns with China on reported human rights violations and abuses, including in Xinjiang and Tibet. We reiterate our concerns over the continued erosion of Hong Kong's autonomy, rights and freedoms."
Hayashi states Japan, G7 positions on China and Taiwan
Hayashi spoke about China and Taiwan at a press conference following the talks.
On China:
"I have a sense of crisis that East Asia may be the next Ukraine. Looking at the Indo-Pacific region, attempts to unilaterally change the status quo by force in the East China sea and South China sea continue, and military activities around Japan are becoming more active. For the first time, the G7 had in-depth discussions on the security environment in East Asia.
"We also agreed to regularize discussions on the Indo-Pacific within the G7 framework. And as the G7, we shared concerns about the expansion of China's nuclear capability and confirmed the importance of transparency in this regard. We also urged China to promptly engage in dialogue with the US on strategic risk reduction."
On Taiwan:
"It has been the consistent position of the Japanese government that peace and stability across the Taiwan Strait are essential not only for the security of our country, but also for the security and prosperity of the international community as a whole. Japan expects the issues regarding Taiwan to be resolved peacefully through dialogue.
"At this G7 Foreign Ministers' Meeting, we confirmed the importance of peace and stability in the Taiwan Strait, which is an essential element for the security and prosperity of the international community. And we called for a peaceful resolution of cross-strait relations.
"The Japanese government has sent a clear message on the importance of peace and stability in the Taiwan Strait to China. We have also expressed a clear message by working closely with the international community, including the G7. We hope to continue these diplomatic efforts in the future."
China reacts sharply to G7 statement
China says the joint statement by the G7 foreign ministers interfered with its internal affairs and discredited the country.
"[The statement] was full of arrogance, prejudice against China and we have made a strong demarche to the host country Japan," said Chinese Foreign Ministry Spokesperson Wang Wenbin.
US warship sails through Taiwan Strait
The US Navy says it sent a warship through the Taiwan Strait on Sunday. The move comes less than a week after China conducted a series of military exercises in the area.
The US Navy's 7th Fleet said the destroyer USS Milius conducted a "routine Taiwan Strait transit" in accordance with international law. It added the transit demonstrates Washington's commitment to a free and open Indo-Pacific.
China said it monitored all the actions of the US fleet and was on alert during the transit. It issued a warning to the US, saying it will protect its sovereignty and security, as well as the peace and stability of the region.
Chinese intelligence-gathering ship sails around Japan
Japan's Defense Ministry says a Chinese intelligence-gathering vessel has entered the East China Sea after completing a voyage around the Japanese archipelago.
The Maritime Self-Defense Force confirmed a Chinese naval ship was sailing southwest in the Pacific Ocean about 70 kilometers northeast of Tanegashima Island, Kagoshima Prefecture, at around 2 p.m. on Saturday.
It then entered the East China Sea, following a passage through the Osumi Strait on Sunday, to cap a roughly half-month voyage around the Japanese archipelago.
The vessel started the trip by entering the Sea of Japan from the East China Sea via the Tsushima Strait on March 28. It passed through the Tsugaru Strait in northern Japan to enter the Pacific.
The ship then traveled south, passing through the contiguous zone near the Izu Islands, just outside Japan's territorial waters, on April 10.
A Chinese naval intelligence-gathering ship was spotted making a similar trip last June through July.