SONSONATE, El Salvador/TAPANATEPEC, Mexico - A new group of migrants bound for the United States set off from El Salvador and crossed into Guatemala on Sunday, following thousands of other Central Americans fleeing poverty and violence who have taken similar journeys in recent weeks.

The group of more than 300 Salvadorans left the capital San Salvador on Sunday. A larger group of mostly Hondurans, estimated to number between 3,500 and 7,000, who left their country in mid-October and are now in southern Mexico, has become a key issue in US congressional elections.

A third group broke through a gate at the Guatemala border with Mexico in Tecun Uman on Sunday, and clashed with police. Local first responders said that security forces used rubber bullets against the migrants, and that one person, Honduran Henry Adalid, 26, was killed.

Six police officers were injured, said Beatriz Marroquin, the director of health for the Retalhuleu region.

Mexico's Interior Minister Alfonso Navarrete told reporters on Sunday evening that federal police did not have any weapons, even to fire plastic bullets.

He said that some of the migrants had guns while others had Molotov cocktails, and this information had been passed on to other Central American governments.

Major issue before Nov 6

Guatemala's government said in a statement that it regrets that the migrants didn't take the opportunity for dialogue and instead threw stones and glass bottles at police.

US President Donald Trump and his fellow Republicans have sought to make immigration a major issue ahead of Nov 6 elections, in which the party is battling to keep control of the Congress.

US Homeland Security Secretary Kirstjen Nielsen on Fox News Sunday said Trump was determined to use every authority he had to stop immigrants from crossing the border illegally.

"We have a crisis at the border right now. ... This caravan is one iteration of that but frankly we essentially see caravans every day with these numbers," she said.

"I think what the president is making clear is every possible action, authority, executive program, is on the table to consider, to ensure that it is clear that there is a right and legal way to come to this country and no other ways will be tolerated," Nielsen said.

Trump has threatened to shut down the border with Mexico and last week said he would send troops.

US Defense Secretary Jim Mattis said on Sunday that the US military has already begun delivering jersey barriers to the southern border in conjunction with plans to deploy active duty troops there.

The additional troops will provide logistical and other support to the Border Patrol, and will bolster the efforts of the approximately 2,000 National Guard forces already there. The new forces are expected to provide logistical assistance such as air support and equipment, including vehicles and tents.

National Guard troops routinely perform those same functions. But active duty troops are rarely deployed within the US except for domestic emergencies like hurricanes or floods.

Reuters - AP