Israeli security forces are on high alert and the government is promising swift and harsh retaliation for Wednesday's bomb attack at a Jerusalem University that killed seven people, including five Americans.

Israel is on a high security alert amid reports throughout the day that armed Palestinian militants were on their way to Israel to carry out more attacks. Additional police were dispatched to Jerusalem and elsewhere and checkpoints were set up along roads in the Sharon area of central Israel.

The heightened alert follows Wednesday's bomb attack at Jerusalem's Hebrew University. A remote controlled bomb was set off in the university's crowded cafeteria, killing seven people, including five American citizens.

The militant Islamic group Hamas, which claimed responsibility, said the attack was in retaliation for last week's Israeli air strike on Gaza City, which killed a senior Hamas leader and 14 other Palestinians, including nine children.

The Israeli government is now vowing swift and harsh retaliation for Wednesday's bomb attack. The government has already discussed further measures against the families of suicide bombers. The Israeli military destroyed the family home of a young Palestinian who blew himself up in central Jerusalem on Tuesday, killing himself and injuring seven other people. The Israeli government is also threatening to expel relatives of suicide bombers from the West Bank to Gaza.

The government says such measures are necessary to show that attacks against Israel carry a heavy price and to thus deter future attacks. Palestinians insist the actions amount to collective punishment that is against international law.

In particular, the threat of sweeping deportations has drawn international criticism.