CAIRO (Reuters) -- Egypt's Muslim Brotherhood said Monday that the attack on a police station in Sinai in which 16 policemen were killed "can be attributed to Mossad," a claim swiftly dismissed by Israel.

The Muslim Brotherhood said on its website that Mossad, the Israeli intelligence agency, was trying to abort the Egyptian uprising that toppled President Hosni Mubarak last year and that it was "imperative to review clauses" of the agreement between Egypt and Israel.

"This crime can be attributed to the Mossad, which has been seeking to abort the revolution since its inception and the proof of this is that it gave instructions to its zionist citizens in Sinai to depart immediately a few days ago."

"(It) also draws our attention to the fact that our forces in Sinai are not enough to protect it and our borders, which makes it imperative to review clauses in the signed agreement between us and the zionist entity," the group said.

Egypt branded the Islamist gunmen behind the attack as "infidels" and promised on Monday to launch a crackdown following the massacre that has strained Cairo's ties with both Israel and Palestinians.

Israel denied any involvement in the attack and dismissed the Brotherhood's claim as "nonsense."

"Even the person who says this when he looks at himself in the mirror does not believe the nonsense he is uttering," Foreign Ministry spokesman Yigal Palmor said.

The bloodshed represented an early diplomatic test for Mursi, who took office at the end of June after staunch US ally Hosni Mubarak was overthrown last year in a popular uprising.

Mubarak had cooperated closely with Israel on security and suppressed Islamist movements such as Mursi's Muslim Brotherhood which rejects violence to achieve its goals but whose leaders often voiced hostility towards Israel.