belagern
to besiege
To surround a city, fortress, or other place militarily with troops in order to force surrender.
Die Armee belagerte die feindliche Festung monatelang.
The army besieged the enemy fortress for months.

to besiege
Loading your saved state.
to besiege
To surround a city, fortress, or other place militarily with troops in order to force surrender.
Die Armee belagerte die feindliche Festung monatelang.
The army besieged the enemy fortress for months.

The verb 'belagern' (to besiege) is inseparable. The prefix 'be-' remains firmly attached to the verb stem 'lagern' in all sentence forms and tenses and is never separated.
Die Fans haben den Star nach dem Auftritt belagert.
The fans besieged the star after the performance.
'Belagern' (to besiege) is a transitive verb and always requires a direct object in the accusative. You ask: Wen oder was belagert jemand? (Whom or what is someone besieging?)
Die Kinder belagerten die Eisdiele.
The children besieged the ice cream shop.
The meaning of 'belagern' (to besiege) becomes clear from the context. Military or historical terms like 'Armee' (army), 'Festung' (fortress), or 'Stadt' (city) point to the literal meaning. Words like 'Fans' (fans), 'Journalisten' (journalists), or 'Kinder' (children) point to the figurative meaning.
Die Ritter belagerten die Burg für mehrere Wochen.
The knights besieged the castle for several weeks.
In the figurative meaning, the verb is often used with groups of people who crowd around a person or place. Typical subjects are 'Fans' (fans), 'Reporter' (reporters), 'Fotografen' (photographers), or 'Kinder' (children).
Die Fotografen belagerten das Hotel des Filmstars.
The photographers besieged the film star's hotel.
to occupy / fill / cast
'besetzen' and 'belagern' can both have to do with control over, or pressure on, a place. 'besetzen' means that you take over a place and have control there, for example a territory or a building. 'belagern' means that you surround a place from the outside or press in on it in large numbers. So you are not necessarily inside the place. The words can be confused because both can sound military. In everyday language, 'belagern' is also used when many people surround someone or something.

Nach dem Konzert belagerten viele Fans den Ausgang.
After the concert, many fans besieged the exit.
Aktivisten besetzten das leere Haus, um gegen hohe Mieten zu protestieren.
Activists occupied the empty house to protest against high rents.