Iranian President Hassan Rouhani said on Monday stability could not be achieved in the Middle East without Tehran's help, responding to criticism of the Islamic Republic from US President Donald Trump who is visiting the region.

Rouhani, a pragmatist who won a new fresh mandate in a May 19 presidential election, also dismissed a summit Trump attended at the weekend in Saudi Arabia as a “ceremonial (event) that had no political value and will bear no results”.

“Who can say regional stability can be restored without Iran? Who can say the region will experience total stability without Iran?” Rouhani said.

Rouhani also said last week's election showed Iranians wanted more democracy and interaction with the world, adding this would lead to much-needed economic progress.

Relations with the United States a curvy road

Rouhani described relations with the United States as “a curvy road.”

He said the Islamic Republic still is waiting to understand what the Trump administration wants. Rouhani said Iranians are “waiting for this government to be civil” and that “hopefully, things will settle down ... so we could pass more accurate judgements.”

Rouhani described the Trump's visit to Saudi Arabia as a “show-off” that “will not have any political and practical values.”

The Iranian president added that “the issue of terrorism cannot be solved through giving money to superpowers.”

Ballistic missile programme will continue

Rouhani said Tehran would continue its ballistic missile programme, state television reported, striking a defiant note after strong criticism from Donald Trump.

“The Iranian nation has decided to be powerful. Our missiles are for peace and for defence ... American officials should know that whenever we need to technically test a missile, we will do so and will not wait for their permission,” Rouhani said in a news conference, broadcast live on state TV.

Rouhani also criticised Iran's arch-foe Saudi Arabia over its lack of democracy, urging Riyadh to allow its people to decide their country's fate through free elections.