A member of Hamas detained for arms smuggling said he was ordered to monitor a Jordanian intelligence officer, according to a televised confession broadcast on state TV on Thursday.
The TV showed clips of stockpiles of weapons, including dozens of hand grenades and some Iranian-made Katyusha rockets, that were seized when Jordanian police arrested the Hamas activists in raids that began April 18.
In his confession, Ayman Naji al-Daraghmeh, 34, said Hamas instructed him to watch a certain Jordanian intelligence officer, but he did not explain why the Palestinian militant group wanted the officer to be monitored.
"They said this officer has harmed the movement," said al-Daraghmeh, who looked relaxed in the video tape and had a long beard.
Jordan said Wednesday that it had arrested more than 20 Hamas activists for smuggling weapons into the kingdom with a view to attacking various sites and military and civilian officials. The government had previously said the weapons were smuggled from neighboring Syria.
Hamas officials, along with the Syrian government - which hosts Hamas' exiled leadership - have denied the accusations.
In giving details of the arrests on Wednesday, government spokesman Nasser Judeh said Jordan would "hold whoever responsible for - God forbid - any action or incident" in the kingdom.
The remark was seen as an implicit warning to the Hamas-led government of the Palestinian Authority.
A security delegation from the Authority received a government briefing on the arms stockpiles on Wednesday.
The discovery of the weapons cache hurt Jordan's relations with Hamas. The day after the stockpiles were revealed last month, Jordan cancelled a planned visit by Palestinian Foreign Minister Mahmoud Zahar, the leader of Hamas in Gaza.
Amman's relations with Hamas have been strained for years. Jordan, a longtime US Arab ally and a peace partner with Israel, once expelled the current overall leader of Hamas, Khaled Mashaal, for his activities.
Jordan has called on Hamas to accept an 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.
The weapons plot has raised speculation by Hamas supporters here that Jordan was bowing to US pressure to further undermine Hamas. The Islamic Action Front, Jordan's largest opposition group and a known Hamas sympathizer, accused the government of exaggerating the arms discovery.