Citing security concerns, the Israeli defense establishment has rejected the individuals' requests for entry into the country despite the fact they all suffer from either heart conditions or cancer, Haaretz reported Sunday.

Physicians for Human Rights Chairman Danny Filk accused Israeli officials of rejecting the ailing individuals' requests in reaction to Hamas' takeover of the Gaza Strip this year.

He said the six are all in desperate need of urgent medical care and warned their conditions could worsen if they aren't granted entry into Israel soon.

"The medical conditions of those patients can degenerate from day to day, and weeks of delays -- that's a lot of time. Maybe it's not a matter of months, but it doesn't take months for a condition to become irreversible," he said.

Defense officials said they are reviewing the individuals' cases, but added the review process was a complex procedure, the Israeli newspaper reported.