Pakistan, Feb. 7 -- The United States (US) and Iran have signalled tentative progress following indirect negotiations in Oman, with both sides describing the talks as constructive while warning that major challenges remain.

US President Donald Trump said on Friday that Washington held "very good talks" with Iran after delegations from the two countries met in Muscat through Omani mediation. Speaking to reporters aboard Air Force One, Trump said further discussions were expected early next week, but warned that "the consequences are very steep" if Tehran fails to reach an agreement.

Read More: Iran, US nuclear talks in Oman were a good start, FM Araghchi says

Iranian officials also struck a cautiously optimistic tone. Foreign Minister A...