Also, a security source confirmed that Palestinian intelligence Chief Majid Faraj was part of the convoy but was not hurt either.
In October, Hamas and the Palestinian Authority began reconciliation talks, but those have bogged down, even as shortages of clean water, medicine and other necessities have fueled concerns that the dispute could boil over into violence.
A second device failed to explode, the official said. Hamdallah immediately returned to the West Bank after delivering the speech.
"We all know that none of this will be easy", he added, "everything we do must be done in a way that ensures we do not put the security of Israelis and Egyptians at risk - and that we do not inadvertently empower Hamas, which bears responsibility for Gaza's suffering".
The official said that Rami Hamadallah crossed Erez Crossing towards the Western Bank shortly after a quick visit to the water plant, without meeting any of Hamas' officials. One auto door also appears to have blood on it.
As soon as the convoy of the two senior officials crossed the checkpoint and drove a couple of kilometres into the coastal enclave, just near the northern Gaza Strip town of Beit Hanoun, a roadside bomb had suddenly exploded right after the convoy of some 20 vehicles and cars already passed by.
"We will hear Fatah saying that some members of Hamas do not want reconciliation, and likewise, we will hear Hamas saying this could have been a fabricated attack by Fatah's security services", Ibrahim said.
EU to respond within 90 days if not exempt By
EU Trade Commissioner Cecilia Malmstroem said the bloc was "not preparing for battle" but had to be ready to protect its industry.
The United Nations Mideast envoy also condemned the attack.
The attack casts a shadow over reconciliation efforts by rival Palestinian governments.The Islamic militant group Hamas expelled the Palestinian Authority to the West Bank during a civil war in Gaza in 2007; but past year they launched talks to try to settle their differences and return Gaza to Palestinian Authority control.
They were due to open a sewage treatment works in Gaza, financed by the PA.
Israel, with help from Egypt, has kept Gaza under a strict blockade for years, and conditions in Gaza have grown increasingly dire.
Extremists opposed to Hamas also operate within the Gaza Strip and have regularly been behind unrest.
The "grave incident must be promptly investigated and the perpetrators brought to justice", Mladenov said. "Wishing a speedy recovery to the injured", Greenblatt said.
Akeeleh said efforts are in place to pardon Israel from making compromises to ease Gaza's humanitarian situation.
In January, Trump announced the U.S. government would be cutting more than half of its planned funding to the United Nations agency for Palestinian refugees, a move that could prove catastrophic for millions of people in need.