Belarus's forced diversion of a plane to arrest dissident journalist Roman Protasevich has prompted outrage. FRANCE 24 looks at precisely how it broke international law and what - if anything - can be done about it.

The forced diversion of a flight between two EU members, Greece and Lithuania, operated by Irish airline Ryanair, provoked fury among Western politicians.

The Republic of Ireland strongly condemned the forced diversion of the flight, with Foreign Minister Simon Coveney telling public broadcaster RTE that "this was effectively aviation piracy, state-sponsored".

Ahead of an EU meeting to discuss Belarus's act later on Monday, Coveney warned that "we cannot allow this incident to pass on the basis of warnings or strong press releases; I think there has to be real edge to the sanctions that are applied on the back of this".

Belarus's act may have contravened the 1944 Chicago Convention on International Civic Aviation, the UN's International Civic Aviation Agency (ICAO) warned. Belarus's forced diversion of the plane was "inconsistent with the rules of international law", the International Air Transport Association said in a statement.

Lithuania was the first nation to take concrete action, ordering on Monday afternoon that all flights to and from its airspace must avoid Belarusian airspace.

FRANCE 24 discussed the legal implications of the forced diversion with Marco Roscini, a professor of international law at the University of Westminster.

What international laws were broken in the Belarus flight diversion?

Article 1 of the Chicago Convention provides that a state has "complete and exclusive sovereignty over the airspace above its territory". When overflying a state's national airspace, therefore, civil aircraft are subject to the full jurisdiction of that state and can be intercepted and ordered to land at the indicated airport. Article 3 bis (a) of the Chicago Convention, however, also specifies that "in case of interception, the lives of persons on board and the safety of aircraft must not be endangered".

So the interception by the military jet and the redirection of the plane to a more distant airport could have potentially endangered the safety of crew and passengers - this will have to be established by an impartial investigation. Appendix 2 of Chicago Convention also states that interception should be undertaken only as a last resort, so the question is whether the Belarusian authorities first requested the plan to land (which I am not sure is the case) or whether they sent the military jet straight away.

As to the fake bomb threat claimed by Belarus as the reason for the interception, Article 1 of the 1970 Montreal Convention for the Suppression of Unlawful Acts against the Safety of Civil Aviation (ratified by Belarus) states that "a person commits an offence if he unlawfully and intentionally ... communicates information which he knows to be false, thereby endangering the safety of an aircraft in flight". Under Article 10 of the Montreal Convention, a state must take 'all practicable measures' to prevent the commission of this and other acts. If, in spite of this, the offence is committed, the state must "facilitate the continuation of the journey of the passengers and crew as soon as practicable". So under this provision Protasevich should be allowed to proceed to Vilnius.

To what extent does this set a worrying precedent for dissidents travelling over the airspace of countries hostile to them?

It does set a worrying precedent for dissidents - that's why it is important that Belarus faces the legal consequences of committing the wrongful act and provides full reparation.

The flight diversion is on the agenda for the EU's meeting today - but sanctions have not exactly been effective at enforcing international law in the past. How, if at all, can international aviation law be enforced when countries like Belarus do such things?

Apart from sanctions, there is potentially another remedy. Under Article 84 of the Chicago Convention, disagreements between the states parties with regard to the interpretation or application of the Convention and its Annexes can be decided by the ICAO Council on the application of any state concerned (the Republic of Ireland - where Ryanair is based? Poland - the state of registration of the aircraft? The states of nationality of the passengers?).

The decision can be appealed before an ad hoc arbitral tribunal agreed upon with the other parties to the dispute or to the UN's International Court of Justice in The Hague. Sanctions, however, will still be important to enforce any decisions or judgments if Belarus refuses to comply with them.

Originally published on France24