Observers, though, said that Mr Aliyev may have been feeling the heat from a sharp drop in the economy and growing unease among Azerbaijanis over accelerating inflation and a 50% cut in the value of the manat currency. They said that he may have wanted to extend a peace offering to the European Union, a vital trade partner, with which he has quarrelled over human rights.

Among those released were human rights campaigners Taleh Khasmamadov, Hilal Mammadov and Rasul Jafarov, opposition activist Nemat Panahli, exelection watchdog chief Anar Mammadli and journalist Parviz Hasimov.

They had all been arrested and jailed in the past three years for holding illegal weapons, drugs dealing or financial crimes.

Their supporters say that these charges have simply been trumped up to crackdown on dissenters in politics and the media.

Khadija Isamayilova, a journalist who focused on corruption and was jailed last year in a case that attracted worldwide media attention, was not pardoned.

On the same day that the prisoners were released, the deputy head of the Presidential Administration, Novruz Mammadov, was briefing Azerbaijani media about improved relations with the European Union.

He said that a new document bringing together the EU and Azerbaijan was likely to be signed soon.

“I have no doubt about that, because, recently, the EU commissioners for foreign affairs and energy issues visited Azerbaijan and expressed their position on the essence of the relations,” the Trend news agency quoted him as saying.

One of the more significant visits by EU officials over the last few months was Federica Mogherini, the EU’s foreign affairs commissioner. She talked up relations between Azerbaijan and the EU.

The European Union is so important to Azerbaijan because it is on the brink of becoming its biggest market for gas from the next phase of its Caspian Sea development.