The Liberal Democrat MP for Bradford East was accused of inciting violence and faces a fresh disciplinary investigation after backing Hamas rocket attacks on Israel.
David Ward was suspended by the party for several weeks last year after making a string of controversial comments about Israel and Jews.
Now his future is once again in doubt after he used social media to give his verdict on the violence currently rocking the Middle East.
"The big question is - if I lived in Gaza would I fire a rocket? - probably yes," he posted on Twitter.
The party said it "utterly condemned" the remarks which "are not representative of the Liberal Democrats".
"Nick Clegg has been at the forefront of calling for peace in Israel and Gaza," a spokesman said in a statement.
"The party takes this matter very seriously and will treat it as a disciplinary issue."
Conservative Party chairman Grant Shapps called on the MP to withdraw the remark, which Labour said was a "vile" comment by a "desperate" MP.
"Appalling: No MP should Tweet what's essentially incitement to violence," Mr Shapps said. "Mr Ward must withdraw now. Completely irresponsible."
Another Lib Dem MP, Stephen Williams, distanced himself from his party colleague's views.
"I think Israel's response is heavy handed but Hamas rocket firing is deplorable too," he told him. "I've seen school bomb shelters in S Israel."
Mr Ward, the MP for Bradford East, had the party whip restored in September after serving a suspension over a series of clashes with the Lib Dem hierarchy over his views on Israel and its treatment of the Palestinians.
The final straw for leadership was a posting in July last year questioning the future existence of the state of Israel which the party said broke a previous agreement to use "proportionate and precise" language when commenting on the issue.
Mr Ward condemned that ruling as "disproportionate" saying such views were widely shared.
A Labour spokesman said: "At a time when all sides should be working for a ceasefire and a peaceful settlement, it defies belief that a Liberal Democrat MP should tweet something so vile and irresponsible.
"Nick Clegg must act immediately to disassociate his party from this comment."
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