An Israeli tank fired into the Gaza Strip on Tuesday, killing a Hamas militant in what the army described as retaliation for the wounding of a soldier and a brief incursion during a violent Palestinian border protest.

An Israeli official said Prime Minister Benjamin Netanyahu also canceled a Qatari donation of $15 million for the impoverished enclave that had been due on Wednesday as part of international efforts to head off escalation.

The Gaza border has simmered since Palestinians launched weekly demonstrations last March to press for the lifting of an Israeli-led blockade on the impoverished territory and rights to family lands lost to Israel in the 1948 war of its foundation.

Palestinian medics in Gaza said a Hamas militant died and two others were wounded in the Israeli shelling of a lookout post near the fortified frontier in the central sector of the enclave ruled by the Islamist group.

Hamas confirmed the three casualties as its members.

Earlier on Tuesday, the army said in a statement, one of its officers was shot at as he faced Palestinian rock-throwers at the fence. The bullet struck his helmet, lightly injuring him, the army said, adding that during the incident two Palestinians also crossed into Israel before returning to Gaza.

Gaza’s health ministry says more than 220 Palestinians have been killed by Israeli forces in 10 months of protests.

Worried about a potential flare-up into full conflict, Egypt and the United Nations have sought to calm Gaza, while Qatar in November pledged $150 million in donations, to be transferred via Israel over six months, in hope of easing economic pressure.

A third Qatari payout of $15 million was due on Wednesday, after it was previously held up by Israel in protest at border violence. An Israeli official, announcing the new postponement, did not say when the payout might now take place.