The chief of U.S. Border Patrol for the San Diego, Calif., region said Monday that 42 people who charged at and attempted to illegally enter the U.S. from Mexico on Sunday were arrested, but many others were able to evade federal law enforcement.

"We ended up making about 42 arrests. Only eight of those were females, and there were only a few children involved. The vast majority of those were adult males," Border Patrol San Diego Sector Chief Patrol Agent Rodney S. Scott said on CNN Monday morning.

[More: Mexico deporting nearly 500 migrants after California border blitz]

"To be completely frank, there were numerous people that actually made it across the border," Scott said. "We’re in the process of building a new border wall here but we don't have it completed. There were some sections that had dilapidated border wall that was made out of scrap metal the military gave us. The group breached a couple sections of that, actually tore down one small section, and started to rush across. And that’s the time they started assaulting our agents, and we were able to hold them back using riot techniques."

U.S. Customs and Border Protection, which is in charge of all port activity, closed down the San Ysidro port of entry late Sunday morning local time as hundreds of migrants who traveled from Central America as part of a caravan attempted to storm the border and pass through less-secured parts of the fence, which is in the process of being swapped out for a taller wall.

Border Patrol Chief Carla Provost told Fox News Monday that 1,000 people of the 6,000 caravan migrants staying in Tijuana, Mexico, tried to rush the border. That number is higher than original estimates of hundreds from Sunday.

Provost did not say if additional rushes like Sunday's are expected this week or the near future.