Iran�s Foreign Minister Javad Zarif says progress has been made in nuclear talks in Lausanne aimed at reaching an initial agreement aimed at curbing Tehran�s nuclear activities in exchange for�sanctions relief.�

Zarif spoke to reporters after separate meetings with his French and German counterparts, Laurent Fabius and Frank-Walter Steinmeier, who earlier on March 28 joined the negotiations in the Swiss city.

Zarif said: �I think there are many signs that we can move forward.�

"I think we can, in fact, make the necessary progress to be able to resolve all the issues and start writing them down in a text that will become the final agreement once it's done," he added.

The talks have entered a sensitive stage as Iran and global powers are determining whether they can bridge differences and reach a political framework agreement by a�March 31 deadline.

The deadline for a final deal is June 30.

Fabius told reporters as he arrived that the talks have been "long and difficult," adding, "We've advanced on certain issues, not yet enough on others."

Asked later after meeting Zarif and separately with U.S. Secretary of State John Kerry if progress was being made, Fabius said: "We're working, we're working. We're trying to make progress."

Steinmeier said the negotiations were in the "endgame."

He said: �Closing the nuclear negotiations with Iran may help to bring some calm to this troubled region.�

Iranian nuclear agency chief Ali Akbar Salehi described one or two issues as becoming "twisted." He told Iran's ISNA news agency that the sides were working to resolve the difficulties.

Earlier in the day, Zarif met with U.S. Secretary of State John Kerry amid reports that the foreign ministers of Russia, Britian, and China were due to join the talks.

The EU's foreign policy chief Federica Mogherini also confirmed she would be arriving in Lausanne later on March 28.

Iran denies accusations that it is trying to secretly develop a nuclear weapons capability, claiming it only wants to develop civilian nuclear power for domestic needs.

Speaking in Washington on March 27, White House press secretary Josh Earnest said the talks in Lausanne could continue into early next week.

Earnest told reporters: �We�ve been negotiating for more than a year, and if Iran is serious about making these commitments, then we�ll be able to reach an agreement by the end of March.�

By Radio Free Europe/Radio Liberty