"This was in response to the attack against an IDF [Israeli army] force in the area of Kissufim on the morning of January 27th, in which one IDF warrant officer was killed and three other IDF personnel were wounded, including one severe injury, when Palestinians detonated an explosive device against an IDF force patrolling on the Israeli side of the Gaza Strip security fence."
Todd Baer, Al Jazeera's correspondent in Rafah, said: "People we are talking to here say this latest round of Israeli strikes started at around 2 o'clock this morning.
"They say they heard three strikes in a row. It hit this area hard where all the tunnels are but there have been no reports of any injuries or damage to homes in the area. But fear is as high as it can be here."
Israel says the attacks on the Rafah tunnels are aimed at stopping alleged weapons smuggling into the Gaza Strip by Hamas fighters.
The tunnels are also used to smuggle food, fuel and consumer goods from Egypt and are considered a life-line for thousands of ordinary Gazans.
Amid the continuing tension, George Mitchell, the US envoy to the Middle East, is on a tour of the region aimed at promoting a durable peace between Israel and the Palestinians.
He began a series of meetings with regional leaders on Wednesday, holding talks with Hosni Mubarak, the Egyptian president, in Cairo.
Mitchell and Mubarak discussed an Egyptian initiative aimed at restoring relative calm between Israel and the Palestinians and the re-opening of Gaza's border points.
"The United States is grateful to Egypt for its leadership in bringing about a ceasefire. It is of critical importance that the ceasefire be extended and consolidated," Mitchell said after the meeting.
"The United States is committed to vigorously pursuing a lasting peace and stability in the region. The decision by President Obama to dispatch me to this region less than one week after his inauguration is clear and tangible evidence of this commitment."
Mitchell is set to meet Shimon Peres, the Israeli president, and Ehud Olmert, the Israeli prime minister, in Jerusalem later on Wednesday.
He is due to travel to the Palestinian West Bank on Thursday.
Al Jazeera's Barnaby Phillips, reporting from Jerusalem, said: "Mitchell has turned into a little bit more of a firefighter than he originally thought when he scheduled this tour.
"The original intention, as US president Barack Obama said yesterday, was that Mitchell would go to the Middle East to listen and to learn - to show that the United States is not going to dictate terms in the Middle East."
"Having said all that, the situation on the ground here has deteriorated in the past 24 hours." Hamas member killed
The fresh jet raid on Gaza's tunnels came despite fragile ceasefires declared by Israel and Hamas last week, ending a 22-day Israeli military campaign on Gaza in which 1,300 people were killed.
Another air raid shortly afterwards killed a Palestinian on a motorcycle whom an Israeli army spokesman identified as the planner of the roadside bomb attack.
|Mitchell, left, called for ceasefires to be extended after meeting Mubarak [AFP]
Hamas confirmed that one of its members riding a motorcycle was injured in the attack, which occurred in the town of Khan Younis.
Neither Hamas nor any other group has claimed responsibility for Tuesday's bomb attack targeting an Israeli army patrol along the Gaza border.
After the blast, Israeli soldiers opened fire, killing a Palestinian farmer, Palestinian medical workers said.
Ehud Olmert, the Israeli prime minister, said late on Tuesday that the killing of the man on the motorcycle was only an initial reaction.
Israel's full response was still to come, Israeli media websites reported him as saying.
Despite the latest violence, Egyptian mediators are continuing efforts to persuade Israel and Hamas to negotiate a more permanent ceasefire.
Hamas wants the border crossings into Gaza reopened, including the Rafah checkpoint bordering Egypt, to end the Israeli blockade in the territory.
Israel wants to stop the rocket fire and prevent Hamas fighters from using smuggling tunnels under the border with Egypt to rearm themselves with weapons.
"The Israelis' position is extremely tough," Phillips said.
"They are determined to show that the policy of deterrence - which they believed justified the recent attacks on Gaza - worked ... It makes it a very difficult situation for Mr Mitchell."