A U.S. soldier is being held in Afghanistan for allegedly massacring 16 Afghan civilians, including many women and children. The soldier reportedly left his base on Sunday and attacked civilians in two villages. In one village, he reportedly gathered 11 bodies and set them on fire, including the bodies of four girls younger than six. Some Afghans have claimed more than one soldier carried out the attacks. The massacre comes just weeks after a series of deadly protests over U.S. soldiers burning copies of the Koran at a U.S. air base. Nadir Naderi, an Afghan human rights activist, spoke out.

Nadir Naderi: “These acts will undermine all the efforts of stabilization of Afghanistan, but also it raises serious questions about the discipline into the forces that are involved in Afghanistan, into their operation. It also provides more tools to the hands of the insurgents, to provoke people against the Afghan government and its international partners.”

Afghan President Hamid Karzai said, “This is an assassination, an intentional killing of innocent civilians and cannot be forgiven.” President Obama and Defense Secretary Leon Panetta called Karzai on Sunday to apologize.

Israeli air strikes on Gaza have entered their fourth day. The strikes have killed at least 21 Palestinians and injured 73 others. Three Palestinians died overnight, including a 15-year-old boy. Israeli Prime Minister Benjamin Netanyahu has vowed to continue the strikes for “as long as necessary.” Militants in Gaza have fired 180 rockets into Israel in response to the air strikes. Four Israelis have been injured. Schools have been shut down in the region for two days. Palestinian lawmaker Mustafa Barghouthi accused the Israelis of trying to create the tension of war in the region.

Mustafa Barghouthi: “Israel was trying to break the calm. While Palestinians were committed to the truce, (Israel was trying) to find a way out for its crisis and to create the tension of war in the area.”

Palestinian militants began firing rockets after an Israeli jet killed Zuhair al-Qaisi on Friday in a targeted killing. He was the head of the Popular Resistance Committees militant group.

Memorials were held around Japan and across the world Sunday to mark last year’s earthquake and tsunami that killed about 20,0000 people and triggered a meltdown at the Fukushima Daiichi nuclear power plant. It was the world’s worst nuclear disaster since Chernobyl. About 326,000 Japanese residents remain homeless, including 80,000 evacuated from the vicinity of the Fukushima facility. Authorities have imposed a 12-mile no-go zone around the plant, and residents may never be allowed back. On Sunday, more than 12,000 took part in an anti-nuclear protest in Tokyo forming a “human chain” around the parliament building.

Prentice Koo, anti-nuclear organizer with Greenpeace: “Although no one died right now, but everyone can forecast the impact of Fukushima will last for over a decade or even a century. So for Japan, this kind of well-developed country can’t even—even they can’t handle a nuclear disaster, so it’s really a strong lesson for everyone to know that when nuclear reactors go wrong, no one can control it.”

In campaign news, Rick Santorum and Mitt Romney split a number of weekend caucuses. Santorum easily won in Kansas, while Romney won in Wyoming. Romney also won delegates in Guam, the Northern Mariana Islands and the U.S. Virgin Islands. On Tuesday, voters head to the polls in Alabama and Mississippi — the states are seen as must-wins for former House Speaker Newt Gingrich. On Sunday, Santorum urged Gingrich to step aside.

Rick Santorum: “The Speaker can stay in as long as he wants, but I think the better opportunity to make sure that we nominate a conservative is to give us an opportunity to go head-to-head with Governor Romney at some point, and hopefully that will occur sooner rather than later.”

In other campaign news, the AFL-CIO is expected to officially endorse President Obama on Tuesday. The New York Times reports the union plans to send at least 400,000 union members out to knock on voters’ doors.

Dozens of civilians have been reportedly killed in the Syrian city of Homs in what is being described as a massacre. It is unclear who carried out the killings. Footage posted by opposition activists on YouTube showed men, women and children lying dead in a blood-drenched room. The Syrian state news agency said armed groups kidnapped scores of civilians, killed, and mutilated their corpses. The report of the killings came soon after U.N.-Arab League envoy Kofi Annan left Damascus on Sunday without agreement on a truce or humanitarian access.

Kofi Annan: “Yes, it’s going to be tough, it’s going to be difficult, but we have to have hope. I am optimistic. I am optimistic for several reasons. First of all, I’ve been here for a very short period. Almost every Syrian I’ve met wants peace. They want the violence to stop. They want to move on with their lives.”

U.S. drone attacks killed at least 25 people in Yemen on Friday. The target of the drone strikes were reportedly militants linked to al-Qaeda. Meanwhile, another 20 people died in southern Yemen in air strikes by the Yemeni air force.

In Bahrain, an estimated 100,000 people marched Friday in the country’s largest pro-democracy protest to date. One 22-year-old man died after being struck by a tear gas canister. Hours after the protest was held, an adviser to Bahrain’s King Hamad said the Gulf Arab state would hold a “comprehensive dialogue” soon to end a year-long political crisis. The government also said it may drop charges against many of the doctors and nurses who have been jailed for treating wounded protesters. In related news, Reporters Without Borders today named Bahrain to be an “enemy of the Internet.”

Human rights organizations are criticizing an Egyptian military court for acquitting an army doctor of forcing a virginity test on a pro-democracy protester. According to Amnesty International, Egyptian troops beat, shocked and strip-searched many women arrested during the protests in Tahrir Square last year and forced them to submit to virginity tests. Heba Morayef of Human Rights Watch criticized Sunday’s ruling, saying: “This is a reflection of the fact that the military justice system is not an independent justice system and that the military will protect its own.”

A delegation from the NAACP is heading to Geneva this week to testify before the United Nations Human Rights Council about restrictive new voting laws in several U.S. states. Since last year, 15 states have passed new voting laws. The NAACP says the new laws suppress the votes of the poor, students and people of color. Last week, civil rights leaders, including the NAACP’s Benjamin Jealous, retraced the historic 1963 Selma to Montgomery, Alabama, march to call for voting rights. The NAACP’s decision to seek support from the United Nations has been compared to efforts by the NAACP in the 1940s and 1950s when the group looked to the United Nations and international community for support in its domestic battle for civil rights and against lynching.

More than 50 tomato pickers have ended a six-day fast outside the headquarters of Publix Super Markets in Florida. The Coalition of Immokalee Workers organized the “Fast for Fair Food” campaign in an effort to win better working conditions and pay for the thousands of workers who pick the tomatoes sold in the grocery store. On Saturday, Ethel Kennedy, the widow of the late Robert F. Kennedy, and their daughter, Kerry Kennedy, broke bread with the workers as they ended their fast.

Sherwood Rowland has died at the age of 84. He won the 1995 Nobel Prize for chemistry for sounding the alarm on the thinning of the Earth’s ozone layer.