Jerusalem ? Israel barred a Palestinian delegation from attending a Mideast conference in London and decided to close three Palestinian universities Monday — a relatively muted response to the deadliest suicide attack in nearly a year.

Bombings on the scale of the twin blasts Sunday in Tel Aviv — 22 killed and more than 100 wounded — in the past triggered major Israeli military offensives.

But Prime Minister Ariel Sharon’s options for retaliation are increasingly limited, with Israel’s general election only three weeks away and the United States eager to keep a lid on Mideast violence ahead of a possible strike against Iraq.

An offshoot of a militia linked to Yasser Arafat’s Fatah movement claimed responsibility for Sunday’s bombings, prompting new Israeli accusations that the Palestinian leader encourages and even orders attacks on Israelis.

The Palestinian Authority condemned the bombings and denied any involvement, while Fatah tried to distance itself from the Al Aqsa Martyrs’ Brigade, a militia with ties to the bombers. A spokesman for the Al Aqsa offshoot responsible for the blasts said his group has been receiving money from Iran and would not heed demands by Palestinian Interior Minister Hani al-Hassan to stop attacks in Israel.