Speaking to Motorsport.com in Montreal, Agag couldn’t confirm either nation would have future representation in the championship, but admitted they were the preferred target for the series.

Nissan, whose Leaf is currently the most popular electric vehicle in Japan, was linked to a takeover of sister brand Renault’s works entry, which is still a possibility but is not expected to happen for two more seasons.

Globally, the Nissan-Renault alliance is the most prolific seller of electric vehicles, followed by US make Tesla.

“I hope they [Japanese and American manufacturers] are coming soon," Agag said. "Like everyone, I have heard some rumours, but I cannot confirm anything in that sense.

“We really want to have a Japanese manufacturer, maybe more than one, and I hope that they will come very soon. For us Japan is a key market, and so we want a Japanese and a US manufacturer.

“These are the two pending countries in terms of this. If we get one from Japan and one from the US, we will be in a very good position.”

Toyota unlikely to follow Porsche to FE

The latest manufacturer to sign up to join the series is Porsche, which will wrap up its LMP1 effort in the FIA World Endurance Championship to prepare for a season six Formula E entry.

It's a move that leaves Toyota as the sole manufacturer entry in LMP1 from 2018 onwards, but Motorsport.com understands it is unlikely to follow its WEC rival into FE, at least in the short-term, and that its priority will be to secure its first Le Mans 24 Hours win in 2018.

Agag had held discussions with Toyota about it joining Formula E for the series' inaugural season in 2014/15, but said he was reluctant to try and lure away another manufacturer from WEC.

“We haven’t had too many conversations with Toyota,” he added. “We know them and I visited a couple of years ago when I was in Japan, but we haven’t had anything more than that.

"I think that right now they are probably having a look at their future steps and strategy and then we will see.

"I don’t want to go too far in inviting more manufacturers because then maybe the other championships will be upset with me.”

Additional reporting by Rene Fagnan