Amnesty International said Tuesday it was "gravely concerned" about the impending execution of a Palestinian man convicted of murder in the Gaza Strip. "J.Z.J.", 38, may be executed at any time after his sentencing in December 2010 for abduction and murder, the group says. His appeal was rejected by a military court in February this year. If the sentence is carried out, he is to be executed by firing squad. Three men were executed last week in Gaza, the first of the year. One of them was convicted of treason and the other two for murder, kidnapping and rape. At least eight people were sentenced to death in 2011 and three were executed following unfair trials, Amnesty said. Proceedings in Gaza are known to fall far short of international standards of fair trial, it said.