NOGALES, Mexico -- U.S. Border Patrol statistics indicate that illegal crossings from Mexico into Arizona are rising as the state prepares to enact the nation's toughest immigration law.

The Border Patrol says arrests there have increased 6 percent so far this fiscal year, while overall crossings to the U.S. are down 9 percent. The agency uses apprehensions to estimate the flow of migrants.

Smugglers are opting for easier routes in the southeastern and southwestern corners of the state as the main Arizona desert corridor becomes dangerous because of drug trafficking, migrant monitors said.

Arizona state Rep. John Kavanagh said Tuesday the increase in arrests didn't spur the law taking effect in July, rather factors that mounted over several years.