Washington: The United States on Friday pressed Egypt to follow promises to ensure security in the Sinai following a string of attacks in southern Israel.

The White House denounced the attacks, which left seven Israelis dead, and expressed hope those responsible "will be brought to justice swiftly."

"We condemn the brutal terrorist attacks in southern Israel on Friday in the strongest terms," White House spokesman Jay Carney said in a statement.

"Our deepest condolences go to the victims, their families and loved ones, and we wish those injured a speedy recovery. The US and Israel stand united against terror and we hope that those behind this attack will be brought to justice swiftly," he said.

An Israeli army commander said six Israeli civilians and a soldier were killed in the spate of coordinated attacks on two desert roads near the Red Sea resort town of Eilat.

Security sources said the Israeli army shot dead seven of the attackers, described as militants from Gaza who entered Israel through the Sinai. The ruling Palestinian Islamist movement Hamas denied any involvement.

Israel warned it would hit back hard, and then hit the Gaza Strip with air strikes that Palestinian medics said killed six people.

"This violence only underscores our strong concerns about the security situation in the Sinai Peninsula," US Secretary of State Hilary Clinton said in a statement.

"Recent commitments by the Egyptian government to address the security situation in the Sinai are important and we urge the Egyptian government to find a lasting resolution," the chief US diplomat said.

Israeli officials have said the perpetrators all came from the Gaza Strip, and a senior source said they had entered Israel via the Sinai Peninsula where Egyptian troops recently began a massive operation to root out militants based there.

Earlier, the Israeli army said two attacks had taken place on route 12, a desert road next to the Egyptian border, near Eilat.