The Iran nuclear deal was signed between six countries in 2015 - Iran, US, Britain, Germany, Russia, France and China for lifting economic sanctions on Tehran in exchange for limitations to the country's nuclear programme.
"We are stakeholders in the Vienna agreement and we are going to stay stakeholders", he said.
Wang said China will take an "objective, fair and responsible attitude, keep communication and cooperation with all parties concerned, and continue to work to maintain the (Iran nuclear) deal".
Zarif, after a closed-door meeting with Mogherini in Brussels, said: "My meeting with Mogherini was good and constructive". Ryabkov also warned that the danger of military tensions in the Middle East mounting, after the United States decision to withdraw from the Iran nuclear deal, is growing.
"We hope that with this visit to China and other countries we will be able to construct a clear future design for the comprehensive agreement", Zarif said, speaking alongside his Chinese counterpart, Wang Yi.
The two top diplomats also discussed the latest situation in the occupied Palestine and the Israeli regime's recent atrocities against Palestinians.
Before leaving Iran, Zarif published a government statement via Twitter criticising Trump's "extremist administration" for abandoning "an accord recognised as a victory of diplomacy by the worldwide community".
It reiterated that Iran was preparing to resume "industrial scale" uranium enrichment "without any restrictions" unless Europe provided solid guarantees it could maintain trade ties despite renewed U.S. sanctions.
Trump hit back Saturday evening, tweeted that the accord had failed to contain Iran's militarism.
Rouhani said America's withdrawal from the JCPOA was a "violation of morals".
China has maintained investment and trade relations with Iran, even under the economic sanctions from Western nations before the nuclear deal. "If the European Union leans towards accommodating the U.S., all the progress we have made since 2015 will be lost".
He said he believed both sides were "on the right track" to make sure that the interests of the deal's "remaining participants, particularly Iran, will be preserved and guaranteed".
Mohammad Ali Jaafari, head of the Revolutionary Guards, said the country could not rely on the West.
He said: "What we are going to do tomorrow in Brussels is we are going to have a conversation about what we can do to help United Kingdom firms, European firms have some confidence that they can still do business".
"As far as we are aware, the European troika, China, Iran and Russian Federation have announced their plans to comply with the JCPOA", Lavrov said Monday.
The sentiment was echoed on the streets.