A senior diplomat says a landmark Iran nuclear agreement has been reached after clearing final obstacles. The diplomat says it includes a compromise between Washington and Tehran that would allow UN inspectors to press for visits to Iranian military sites as part of their monitoring duties.

But access at will to any site would not necessarily be granted and even if so, could be delayed, a condition that critics of the deal are sure to seize on as possibly giving Tehran time to cover any sign of non-compliance with its commitments.

“Yes, there is agreement,” said the source who declined to be identified.

Under the deal, the diplomat says, Tehran would have the right to challenge the UN request and an arbitration board composed of Iran and the six world powers that negotiated with it would have to decide on the issue.

The unnamed diplomat says the US weapons embargo on Iran will remain in place for five years.

Further, under the agreement, UN missile sanctions on the country w