The Israeli army has accused Hamas of being behind an attempted bomb attack on a border crossing in the Gaza Strip.
Palestinian security forces foiled the attack on 26 April
The army said that the plot to attack the Karni crossing last week was carried out by the Popular Resistance Committees, under Hamas' direction.
Hamas spokesman Sami Abu Zuhri flatly denied the allegation.
He said that Hamas affirmed the Palestinian people's right to "self-defence" but had nothing to do with the attempted bombing.
The Israeli army statement said that the man behind the attempted attack was Mamtaz Dougmoush. The army alleges that he has been working closely with Hamas.
"Dougmoush and his men have been operating since January 2005 with the full authorisation, funding and guidance of the senior Hamas leadership in the Gaza Strip, thus allowing Hamas to continue to pursue terror activity through them, while maintaining its desired image of non-violence," said the army statement.
Mr Abu Zuhri dismissed the Israeli army statement.
"We affirm the Palestinian people have a right to self-defence. We deny having anything to do with this attack. If Hamas carries out any attack, it claims responsibility officially and clearly. These are Israeli lies," he said.
The attack at Karni last Wednesday was foiled by Palestinian security officers.
The Popular Resistance Committees is an umbrella group for a number of small Palestinian militant groups. It has been responsible for many attacks on Israel, including rockets launched from Gaza in recent weeks.
Hamas has been behind dozens of bombings and attacks since the start of the intifada in late 2000, including suicide bombings inside Israel. However the group has largely held to an informal truce for more than a year.
It has refused international demands to recognise Israel and renounce violence since it won Palestinian parliamentary elections in January 2006.
Karni is the main cargo crossing into the Gaza Strip from Israel.
The Israeli authorities have closed the crossing for long periods this year because of what they say are security concerns.
The UN has said that this has resulted in widespread food shortages in Gaza.