DUBAI, May 22 (Reuters) - Iranian President Hassan Rouhani said on Monday Tehran would continue its ballistic missile programme, state television reported, striking a defiant note after strong criticism of the Islamic Republic from U.S. President 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.

(Additional reporting by Bozorgmehr Sharafedin; Writing by Parisa Hafezi; Editing by Gareth Jones) ((parisa.hafezi@thomsonreuters.com; +90 532 176 3452; Reuters Messaging: parisa.hafezi@thomsonreuters.com))