Israel said it arrested two Palestinian sisters from Gaza on Thursday after they were caught trying to smuggle explosives from Gaza into Israel by hiding them in medicine tubes.
"It is believed they were going to be used in Hamas's future terrorist attacks," Israel's Shin Bet security service said in a statement.
"A preliminary investigation revealed that the explosives were sent by Hamas," read the statement.
The tubes, labeled "medical materials," were found during a routine security inspection on Wednesday at the Erez Crossing, a passageway between the besieged Palestinian enclave of Gaza and Israel.
The sisters' entry into Israel had been approved in order to allow one of them to receive cancer treatment which she suffers from.
Under Israel's restrictive policy, a very limited number of people and goods are allowed both in and out of Gaza.