US and European diplomats said on Saturday they are united in their strategy and goal in trying to achieve a nuclear deal with Iran.

“We are on the same page,” the US secretary of state, John Kerry, said after meeting the French foreign minister, Laurent Fabius. “We know what we are chasing after and we are chasing after the same thing.”

Kerry and Fabius cited progress in the talks, with the last round just wrapping up on Wednesday in Switzerland. But the officials acknowledged big gaps that must be bridged if the sides are to reach a deal by the end of March deadline that the negotiators have set.

“There is progress in certain areas but there are also divergences,” Fabius said.

The next round of talks is set to begin on 15 March.

Kerry said Iran still needed to make decisions that would allow it to prove to the world that it is not trying to develop nuclear weapons. Tehran claims its nuclear programme is peaceful and exists only to produce energy for civilian use.

“We have a critical couple of weeks ahead of us,” Kerry said. “But we are not feeling a sense of urgency that we have to get any deal. We have to get the right deal.”

Iran’s vice-president, meanwhile, said technical roadblocks hampering a final nuclear accord with world powers had been eliminated during ongoing discussions with American negotiators.

Ali Akbar Salehi, who is also in charge of Iran’s nuclear agency, told state television on Saturday that Tehran offered proposals to remove “fake concerns” over the country’s nuclear programme, paving the way for a final deal.

But the hardline daily paper Kayhan slammed the negotiations, saying that an American proposal of a 10-year suspension of Iran’s uranium enrichment activities is a first step aimed at finally toppling Iran’s ruling Islamic government.

Iran and the six-country group – the US, Russia, China, Britain, France and Germany – hope to reach a rough deal on Iran’s disputed nuclear programme by March and a final agreement by 30 June.