The Israeli government agreed to temporarily open the main cargo crossing between Israel and the Gaza Strip on Monday to allow the delivery of basic food items, medicine and other humanitarian supplies running short inside the strip.
But Israeli military officials closed the Karni crossing again just 30 minutes later, citing security concerns.
Karni's brief opening came a day after Israel and the Palestinians, under U.S. supervision, agreed to open a smaller passage farther south for humanitarian supplies to arrive through Egypt. Karni has been closed for most of the year because of what Israeli officials say are specific threats of attack on the passage.
The United Nations and other organizations have warned that the closures are causing shortages of flour, dairy products and other staples for Gaza's 1.3 million residents. The crossing also remains closed to agricultural exports from Gaza, a key element of the strip's economy.
In a sign of unrest caused by economic uncertainty inside the strip, Palestinian police clashed Monday with gunmen from the al-Aqsa Martyrs Brigades, an armed wing of Palestinian leader Mahmoud Abbas's Fatah party. The gunmen blocked roads, including the main highway Abbas planned to use Monday in leaving Gaza after an official visit, and stormed several public buildings to demand government jobs. At least six gunmen were wounded in the fighting, reports Washington Post.