It has just been confirmed that there is volcanic unrest on the Reykjanes peninsula, according to Kristín Jónsdóttir, division head for natural disaster monitoring at the Met Office.
Scientists are still analysing the data, but the measurements indicate the pulses of instability beneath the surface usually expected just before a volcanic eruption.
"That is not to say that we are seing signs that an eruption has started. But it does appear to be the sort of instability pulses we'd expect in the run up to an eruption," Kristín says.
A statement from the Met Office says the pulses began at 14.20.
"It is being recorded on most seismometers and is located south of Keilir, by Litla Hrútar. Such readings are registered in the run up to a volcanic eruption but there is no confirmation that an eruption has begun. Further analysis is underway."
All major radio and TV stations in Iceland will carry the civil protection agency press briefing at 16.00 this afternoon. RÚV English will provide near-live highlights from the briefing.