BOSTON - Homeland Security Secretary Janet Napolitano met privately on Sunday with her successor as Arizona governor as the Obama administration challenges the state's immigration law.

Napolitano, a Democrat, huddled for a half-hour behind closed doors with Republican Jan Brewer in Boston during the National Governors Association summer meeting. Napolitano was in town to provide the governors with a classified national security briefing.

Slated to be implemented July 29, the Arizona law would require state and local police to question and possibly arrest illegal immigrants during the enforcement of other laws such as traffic stops. Last week, the Obama administration filed suit in federal court to block it, arguing that immigration is a federal issue.

Napolitano ignored a request for comment following their meeting, but Brewer said the two did not discuss the lawsuit. Instead, she said they had a cordial conversation centered on her efforts to win Arizona more National Guard troops to guard its border with Mexico, as well as her plea for reconnaissance helicopters and more unmanned aerial vehicles to prevent illegal crossings.

"Our parting words, were, you know, 'I'd be remiss if I didn't ask you for my SCAAP dollars,'" Brewer said with a laugh, referring to money the state believes it is due for incarcerating illegal immigrants under the State Criminal Alien Assistance Program. However, the program is run by the Justice Department, not Napolitano's Homeland Security Department.

Arizona's total prison budget is about $900 million a year, and state officials say illegal immigrants make up about 15 percent of their prison population.

Napolitano, while Arizona governor from 2003 to 2009, routinely sent the federal government bills for reimbursement.

Brewer met with President Barack Obama at the White House last month to discuss the immigration issue.

A week earlier, the president announced he would be stationing up to 1,200 National Guard troops along to border - mostly in Arizona - to bolster border incursion efforts.

Brewer supports a proposal to add 6,000 troops along the southwestern border, with 3,000 stationed in Arizona.