Palestinian Foreign Minister Mahmoud Zahar's visit to Jordan, which was planned for Wednesday, had been "put off until further notice," a Jordanian government spokesman said.

On Friday, Zahar went to Cairo, but Egyptian Foreign Minister Ahmed Aboul Gheit said he was too busy for a meeting.

The Jordanian spokesman, Nasser Judeh, told The Associated Press that "missiles, explosives and automatic weapons were seized in the last couple of days." Hamas activists had managed to smuggle "such dangerous weapons into the country" and store them, he said.

He would not say whether the activists had been arrested.

Osama Hamadan, a spokesman for Hamas, declined to comment on Judeh's remarks, saying late Tuesday he had not seen the Jordanian statement.

In a separate statement to the official Petra news agency, Judeh said Jordanian security services had observed Hamas activists "exploring several vital (potential) targets" in the capital, Amman, and other cities. He did not elaborate.

State television quoted Judeh as saying the discovery of the arms cache proved that "Hamas is using two languages in dealing with Jordan."

Jordan, which signed a peace treaty with Israel in 1994, maintains a tough line on militants and once expelled the current leader of Hamas, Khaled Mashaal, for his activities.

Jordan and Egypt have called on Hamas to accept the Arab peace plan, which entails full recognition of Israel in exchange for full withdrawal from territory captured in the 1967 and 1973 Arab-Israeli wars.

Hamas refuses to recognize Israel.

Hamas officials have been flying around the Middle East to ask for aid, although it was not immediately clear whether that was the purpose of Wednesday's trip. Hamas is hoping for help to compensate for the U.S. and European Union's decisions to cut off funds to the Palestinian Authority because of the militant group's refusal to renounce violence and recognise Israel.