The Israeli air force carried out four strikes on militant targets in the Gaza Strip early Wednesday, eyewitnesses said, hours after a cross-border rocket attack on the Jewish state.

The planes targeted training camps belonging to militant group Islamic Jihad in Rafah, Khan Yunis and Gaza City, the witnesses said. There were no immediate reports of casualties.

Amnesty International accused the Islamist movement Hamas Wednesday of committing war crimes against fellow Palestinians to "settle scores" during last year's Gaza war with Israel, executing at least 23 people.

A report by the London-based rights group detailed the "brutal campaign of abductions, torture and unlawful killings against Palestinians accused of 'collaborating' with Israel" by Hamas, de facto ruler of the Gaza Strip enclave.

A 40-year-old Yemeni, who fought U.S. troops in Iraq and Afghanistan, pleaded guilty in New York Tuesday to conspiring to murder Americans and to supporting al-Qaida, prosecutors said.

Saddiq al-Abbadi, who was arrested with an alleged co-conspirator in Saudi Arabia on a U.S. warrant, now faces a maximum life sentence in an American jail.

Shellfire from Yemen killed one civilian and a member of the security forces in Saudi Arabia on Tuesday, officials said.

The latest casualties bring to at least 28 the number of people, military and civilian, killed in the Saudi border zone since a Saudi-led coalition began air strikes against Iran-backed Shiite Huthi rebels in Yemen on March 26.

Turkey and the United States have started training moderate Syrian rebels on Turkish territory to prepare them to fight Islamic State (IS) militants, the Turkish foreign minister said on Tuesday. 

The U.S.-led program to equip and train Syrian rebels on Turkish territory has started "with small groups" after months of delays, Mevlut Cavusoglu was quoted as saying by the official Anatolia news agency. 

The U.N. World Food Program (WFP) on Tuesday called for a humanitarian ceasefire in Syria to allow farmers in the war-torn country, which is ravaged by food shortages, to harvest their crops.

"With indications that the 2015 harvest in Syria may exceed the last two years’ harvests at a time of massive food insecurity and internal displacement, it is paramount that crops are not lost and that food stays within the country," WFP director Ertharin Cousin said in a statement.

Restrictions on Iraqi people fleeing the fighting in Anbar province are forcing some of them to return straight into conflict areas, an aid group said Tuesday.

"Thousands of people fleeing Ramadi are stuck at checkpoints or being denied entry to safe areas," said Mark Schnellbaecher of the International Rescue Committee (IRC).

Poland will take in 60 Syrian refugee families of the Christian faith, Warsaw said Tuesday just days after it opposed European Union plans for binding quotas on asylum seekers for its 28 member states.

"We'll welcome 60 families for a start," Prime Minister Ewa Kopacz told reporters in Warsaw.

Egypt reopened its Rafah border crossing with Gaza for two days from Tuesday, Palestinian border officials said, for the first time since March.

Maher Abu Sabha, director of border crossings in the Gaza Strip, said traffic was permitted into Gaza only, to allow the return of Palestinians stranded in Egypt.

Yemeni fighters allied with exiled President Abedrabbo Mansour Hadi have retaken the city of Daleh after pushing out Shiite Huthi rebels, local chiefs said on Tuesday.

The insurgents backed by troops loyal to former president Ali Abdullah Saleh had seized Daleh last month as they expanded southwards, triggering deadly confrontations with Sunni tribes and southern fighters.