The great divide

New U.S. citizens take the oath of citizenship during a naturalisation ceremony beneath the Statue of Liberty. If planned immigration reform goes ahead, the estimated 11 million illegal immigrants living in the United States could likewise be given a chance to become citizens.

The legislation is important for President Barack Obama and many other Democrats, partly to support Hispanic voters who turned out overwhelmingly for them in last November's elections. But the issue is also of key importance to Republicans, as Hispanic voters gain increasing influence in U.S. politics.

In parallel to proposed political reform, border controls have tightened considerably. Mexican grandmother Lucia Angulo, pictured standing near the border fence in Tijuana, is one of those affected.

Angulo has entered the United States illegally so often over the past three decades that she has lost count of how many times border patrols caught her. But when she left San Diego to visit her dying mother in Mexico last April, she knew it would be harder than ever to return. Nearly a year later, she was still trying.

U.S. border security was increased after the Sept. 11, 2001 attacks, and tightened further after the 2007-2008 financial crisis, forcing illegal immigrants and smugglers to think harder about how to get over, under or around the frontier.

One way was by sea. In the 2012 fiscal year, 779 people were apprehended illegally crossing the Pacific, up from 230 in 2008, U.S. Border Patrol data show.

There is a trade in smuggling people and drugs across the border by boat, often from small fishing villages like Popotla, south of Tijuana, where the coast is not heavily policed.

A jumble of restaurants, inns and seafood stalls, Popotla hugs a small cove where locals say U.S. gangster Al Capone once used to run contraband. Just like in the era of U.S. Prohibition, things can quickly turn violent there.

A few minutes after telling a Reuters reporter that "there are places nearby" better than Popotla to smuggle people or drugs, a local fisherman calling himself Diego got embroiled in a dispute with a group of men in a white van. Moments later, one of the men was shot in the head and killed by an unidentified gunman.

Migrants trying to get to the United States face brutal challenges and are often caught up by cartels, who seek to make additional money by kidnapping, robbing or killing them at will.

Relatives grieve for one victim of the violence, a Guatemalan immigrant named Victor Enrique Bedolla Ramirez, whose remains were found in a mass grave in Tamaulipas in northern Mexico among a group of 193 immigrants believed to be killed by members of the Zetas drug gang.

Mexico's National Human Rights Commission, or CNDH, said the kidnapping of migrants has been on the rise since 2007 - the same year a military-led crackdown on drug cartels began in earnest under former President Felipe Calderon.

The face of the border has changed as many controls tighten up. Crossings on the Tijuana-San Diego section of the border, for example, are today a fraction of what they once were.

In 1986, when the United States passed a reform that granted amnesty to 3 million illegal immigrants, the Border Patrol arrested 630,000 people crossing into the San Diego area alone.

Last year, fewer than 360,000 people were detained across the entire 2,000-mile (3,200-km) border, and only 28,500 in San Diego.