"We are enriching more uranium before the deal was reached. Pressure has increased on Iran but we continue to progress," Rouhani said on Thursday in a televised speech.
Iranian President Hassan Rouhani has said that his country is enriching more uranium than Tehran did before it agreed to a nuclear deal with world powers in 2015.
Iran has gradually scaled back its commitments under the nuclear deal, signed with the US, China, Russia, Germany, France and the UK, in retaliation to Washington's withdrawal from the pact in 2018 and its reimposition of sanctions that have crippled the country's economy.
Earlier in the week, the United Kingdom, France and Germany challenged Tehran over breaking the limits set out in the deal.
The European nations announced that they triggered the dispute mechanism provided for in the landmark agreement in order to force Tehran to honour its commitments under the accord, formally known as the Joint Comprehensive Plan of Action (JCPOA).
On Thursday the EU's top diplomat Josep Borrell held "frank" direct talks with Iran's Foreign Minister Mohammad Javad Zarif in New Delhi.
"In a frank dialogue, they discussed the latest developments around the Joint Comprehensive Plan of Action," the European Union said in a statement.
The face-to-face talks on the sidelines of a conference were the first following a series of telephone calls since a US drone strike killed top Iranian general Qassem Soleimani on January 3.
EU officials have said Iran already expressed anger at the European move by telephone.