Two bombs planted near an Islamic school in Pakistan killed eight people and injured 42 others yesterday in the latest outbreak of violence gripping the southern port of Karachi.
The bombs were planted near the port.
The bombs were planted near a school, not the port. I think the system got confused because the article refers to the entire town as "a port" but the bombs were not planted near the physical port itself. 
( z1 plant :ARG1 ( z2 bomb ) :ARG1-of ( z3 near :ARG2 ( z4 port ) ) )