Officials said on Sunday that Mahmoud Abbas, the Palestinian president, informed Jordan that the government had turned down his request to join a committee he set up to examine with senior Jordanian officials the evidence they say backs up their charges.
Jordan said last month that rocket-launchers, detonators and explosives seized from a secret Hamas arms cache in the kingdom had been smuggled from Syria, where the Palestinian groups' exiled leadership is based.
A week later it said a group of Hamas activists arrested by its security forces were close to staging attacks on senior Jordanian officials on orders from its Syria-based leadership.
Nasser Joudeh, the government spokesperson, was quoted as telling reporters: "President Abbas showed in the letter that the Palestinian government ... had expressed its lack of desire to participate in this delegation."
Joudeh said the Hamas-led government told Abbas that since Amman had accused its Syria-based leadership of masterminding the alleged smuggling it was more appropriate that Jordan talk with them rather than its Gaza-based leadership.
Hamas has repeatedly denied accusations its members were involved in arms smuggling to Jordan from Syria, and said they would not join a committee to investigate.
"As far as we are concerned, this incident never happened. Therefore, we decided against going," said a Hamas government official in the Gaza Strip.
"The European position will break down over time as the Europeans realise that their position does not serve them"
Palestinian foreign minister
Mahmoud al-Zahar, the Palestinian foreign minister, repeated his denial of Hamas involvement, saying: "We will not interfere in the security of Jordan... We are fully convinced we had nothing to do with this."
Al-Zahar also said he had met a European foreign minister during a three-week tour of Arab countries, but declined to name the minister.
Such a meeting would be a coup for the Palestinian Authority, facing economic meltdown after Western countries froze aid and cut most diplomatic contacts when Hamas took control of the government in March.
"I have met with a European consul during a ceremony and we met with a foreign minister of a European country. There were contacts with many European parties," al-Zahar said, speaking to reporters in Gaza.
Al-Zahar declined to name the officials or say where the meeting took place, saying that could jeopardise tenuous relationships he was trying to build. An official from al-Zahar's office said the minister was from the European Union.
A European diplomatic source in Jerusalem cast doubt on the account, saying it was unlikely such a meeting took place.
The European Union, along with the US, cut direct aid to the government to try to force Hamas to recognise Israel and abide by interim peace deals with Israel.
"The European position will break down over time as the Europeans realise that their position does not serve them," Zahar said. "We are making contacts."