An explosion struck the convoy of the Palestinian prime minister Tuesday as he was visiting Gaza, in what his Fatah party is calling an attack against Palestinian unity.

The blast occurred after the convoy travelled through the Erez crossing with Israel for a visit to a sewage plant project in the northern part of Gaza.

The bombing that seemed to target the Western-backed leader, who is spearheading the authority's reconciliation efforts with Gaza's dominant group, Hamas, happened on the day the White House is due to hold a meeting on the humanitarian situation in the enclave.

There was no immediate claim of responsibility for the blast and Hamas condemned the attack.

Hamdallah, second from the right, is greeted by Hamas security chief Tawfiq Abu Naim, centre, upon the Palestinian prime minister's arrival in Gaza City. (Mahmud Hams/AFP/Getty Images)

Minutes after the explosion, the 59-year-old prime minister, appearing unhurt, delivered a speech at the inauguration of a waste treatment plant and pledged to continue to pursue Palestinian unity.

He said three vehicles were damaged in the explosion, which left a crater by the side of the road and blew out the windows of at least one utility vehicle.

The Palestinian Authority said it held Hamas responsible for the attack, but stopped short of directly accusing the group of carrying out the assault, suggesting it had failed to provide adequate security.

Elusive unity

Hamas and the authority, led by President Mahmoud Abbas, are still divided over how to share administrative power in the Gaza Strip under an Egyptian-brokered unity deal.

The Hamas party won Palestinian legislative elections in January 2006, then consolidated power the following year after factional fighting between Hamas and forces loyal to the Fatah party.

"The attack against the government of consensus is an attack against the unity of the Palestinian people," said Nabil Abu Rdainah, a spokesperson for Abbas.

In a statement, Hamas said the targeting of Hamdallah's motorcade was "part of attempt to damage the security of Gaza and deal a blow to efforts to finalize reconciliation." Hamas-led security forces said they have launched an investigation.

Hamdallah, whose portrait is featured along with Abbas's and those of Hamas leaders on Gaza posters promoting Palestinian unity, is based in the occupied West Bank.

He travelled overland, via Israel, to the Gaza Strip, and police said the motorcade was attacked near the enclave's northern town of Beit Hanoun. He later left Gaza as scheduled in another convoy, with security men clutching automatic rifles standing along the side of his vehicle.

White House holding talks on Mideast

The White House was due to hold a meeting later on Tuesday, addressed by U.S. President Donald Trump's Middle East peace negotiator, Jason Greenblatt, and Trump's son-in-law, Jared Kushner, who are putting together U.S. proposals for a peace agreement between Israelis and Palestinians.

In past years, Palestinian factions opposed to peace talks with Israel have carried out attacks timed to coincide with such initiatives. Israeli-Palestinian negotiations collapsed in 2014.

Hamas has condemned Trump's recent moves to recognize Jerusalem as the capital of Israel and move the U.S. Embassy to the city. The Palestinian Authority, which was also angered by Trump's Jerusalem decision, has refused to participate in Tuesday's White House meeting or meet with Trump's Middle East envoys.

Tuesday's explosion occurred near the spot where a U.S. diplomatic convoy was blown up by a remote-controlled bomb in 2003 shortly after it entered the Gaza Strip. Three American security specialists were killed and a U.S. diplomat was injured.​