Friday, June 28's meeting in Vienna among the remaining signatories of the embattled nuclear deal may be the "last chance" to save the historic accord, Iran warned, according to Al Jazeera.

In comments carried by Iran's Fars News Agency, Ministry of Foreign Affairs spokesman Abbas Mousavi said the gathering in the Austrian capital was an opportunity to see how those still party to the 2015 agreement could "meet their commitments towards Iran".

Concerns abound the deal will collapse after the United States unilaterally withdrew from the accord a year ago and reimposed punishing sanctions on Iran. Fears remain that an Iran-US conflict could break out after an American drone was shot down last week and US President Donald Trump called off retaliatory attacks at the last minute.

Mousavi said despite supporting Iran in several statements, the remaining signatories - the United Kingdom, France, Germany, China and Russia - failed to take any action to shield its faltering economy from US sanctions.

Tehran has threatened to breach the limit of its stockpile of low-enriched uranium mandated under the deal in retaliation to the US approach, which has also seen Trump attempt to choke Iranian oil exports amid a spiralling war of words between Washington and Tehran over multiple flashpoints in the Middle East.

Iran is expected to surpass that limit in days.