State X has a bilateral agreement with State Y, which provides for the reciprocal freedom of movement between their nationals in their respective territories.

In application of this agreement, many nationals of State Y have moved to State X, which is a rich, well-resourced state. Additionally, State Y has granted the authorities of State B, access to its territory for the use military of exercises. After several years the relationship between the two (2) States deteriorates, leading State Y to denounce the existing bilateral treaty and expel all nationals from State B living in State Y.

In an act of protest, nationals from State B called Treaty Front (TF) storm the Embassy of State Y (you can assume the Embassy is on State Y Territory), bombing security posts in the process and injuring State X nationals. On securing the embassy, TF are holding twenty (20) diplomatic staff hostage. The TF from State B, claim that in the expulsion of its citizens has been done so in breach of human rights principles.

State X condemns the action of TF and demands that the government of State Y act to end the siege and see to the release all diplomatic staff, safely. State Y claims they had no prior knowledge of the FT plan.

In response, State BY initiates proceedings before the International Court of Justice (ICJ) claiming that State X has breached their treaty obligations.

State X submits that they made a reservation excluding the application of any bilateral treaty binding upon the parties in the dispute. Further, State X claims that State Y is in breach of International Law with respect to the ongoing siege and injury to nationals at the Embassy.

What issues of international law does the International Court of Justice (ICJ) need to consider in this dispute?

On the facts, which State has the strongest claim, State X or State Y?