GENEVA (Reuters) - The caravan of migrants making its way through Mexico is “kind of a normal event” and the United States ought not to reinforce its border against them, a United Nations official said on Friday.

Migrants, part of a caravan traveling to the U.S., walk north from Huixtla, Mexico November 2, 2018. REUTERS/Leah Millis

With days to go before mid-term elections, U.S. President Donald Trump has called the surge of people an “invasion”, ordered troops to the border and suggested any rock-throwing by migrants should be treated as equivalent to gunfire.

Joel Millman, a spokesman for the U.N.’s International Organization for Migration (IOM), told a U.N. briefing in Geneva there had been similar caravans for many years, and the group was still hundreds of miles away from the United States.

“So (using) words like ‘invasion’ and things like that is assuming that this is a new phenomenon which is a drastic emergency, and I don’t think that anyone at IOM would share that view,” he said.

“This is kind of a normal event.”

Militarised frontiers tended not to deter people from crossing borders, he added. Instead, they increased the profits of criminal people-smuggling gangs and led to deaths among migrants.

“Militarising the border is not something we are ever in favor of,” he said.

The migrant group has become a major issue in campaigning for the elections on Nov. 6, when Republicans will seek to maintain control of both congressional chambers.

“We are calling for humanity and taking things away from politics,” Babar Baloch, a spokesman for the U.N. refugee agency UNHCR, said at the briefing.

Mexico on Wednesday put the size of the migrant group that left Honduras in mid-October at 2,800 to 3,000 people. Others have since followed.

The Pentagon said on Wednesday more than 7,000 troops would support the Department of Homeland Security along the Mexican border. Trump said as many as 15,000 could be sent.