© ReutersPoland's Foreign Minister Radoslaw Sikorski (centre) with other delegates after the deal was agreed.
Poland's Foreign Minister Radoslaw Sikorski was at the centre of negotiations between the Ukrainian government and opposition leaders.

Earlier in the day, the diplomat was overheard telling a Ukrainian opposition leader: "If you don't support this [deal] you'll have martial law, you'll have the army. You will all be dead."

He later told ITV News' Europe Editor James Mates that martial law in Ukraine was a "real possibility" and interior troops were being "readied" up until an agreement was signed.

The foreign minister told ITV News: "Well, as you can see it's almost miraculous. Within minutes of the agreement being signed the riot police are leaving."

The EU-brokered deal concluded that Ukraine will hold an early presidential election and will return to its 2004 constitution with reduced powers for President Yanukovich.