Iran said Tuesday that it would boost its capacity by opening a centre for production of new centrifuges, possibly as early as Wednesday, at the Natanz plant.

Under the 2015 nuclear agreement that Iran signed with world powers, it has the right to build and test certain centrifuges, though detailed restrictions exist for the first 10 years on the types and quantities of the machines.

"Under the current situation, we hope that all parties concerned can proceed with the long-term and overall interests in mind and continue to sustain and implement the agreement," Chinese foreign ministry spokeswoman Hua Chunying told a regular press briefing.

"A comprehensive agreement and a thorough and balanced implementation of its obligations will help maintain the international system to ensure nuclear non-proliferation and help maintain peace and stability in the Middle East," she said.

The move comes a month after President Donald Trump announced the US decision to withdraw from the deal and reinstate sanctions.

The remaining parties -- China, Britain, France, Germany and Russia -- have vowed to stay in the accord.

Many Western companies have already started to wind down Iranian operations, but Beijing, which is Iran's top trade partner and one of the biggest buyers of its oil, has signalled that it intends to keep working with the Islamic regime.

Iran's president, Hassan Rouhani, will meet with Chinese leader Xi Jinping at the summit of the Shanghai Cooperation Organisation, a regional security group, in the eastern city of Qingdao this weekend.

Russian President Vladimir Putin will also attend the conference.