Jordan said Tuesday it was cancelling a visit of the Palestinian foreign minister because activists of his Hamas party had been smuggling missiles and other weapons into the kingdom.
Government spokesman Nasser Judeh said the visit by Palestinian Foreign Minister Mahmoud al-Zahar, which was planned for Wednesday, had been "put off until further notice."
He 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 declined to say whether the activists had been arrested.
Al-Zahar is the most senior Hamas leader in the Gaza Strip.
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.
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.