Mexican President Felipe Calderon denounced Arizona's tough new immigration law as he began a state visit to Washington on Wednesday, putting the contentious issue firmly at the top of his agenda.
U.S. President Barack Obama and first lady Michelle Obama greeted Mr. Calderon and his wife, Margarita Zavala, at the White House at the start of the two-day visit, during which Mr. Calderon and Mr. Obama will meet and attend a state dinner and Mr. Calderon will address a joint session of the U.S. Congress.
Standing by Mr. Obama, Mr. Calderon said that despite their "enormous contribution to the economy and society of the United States" millions of immigrants "live in the shadows, and at times, as in Arizona, confront patterns of discrimination."
Mr. Obama and Mr. Calderon will juggle hot-button issues, including immigration and drug violence, with the pomp and ceremony of a state visit, only the second of Mr. Obama's presidency.
The two countries, whose trade surpasses $1-billion U.S. a day, broadly agree on issues such as the global economy and climate change. There are millions of Mexican-Americans and Mexicans living in the United States and many Americans travel to and live in Mexico.
"The United States and Mexico are not simply neighbours bound by geography and history; we are by choice friends and partners," Mr. Obama said.
But there are tensions over immigration, especially after the passage of the new Arizona law, as well as border security, drug violence and trade. The Arizona law, which comes into force in July, requires police in the border state to check the immigration status of anyone they suspect is in the United States illegally.
Analysts do not expect major new initiatives from this visit and instead will be watching to see how the leaders address difficult issues without upsetting their audiences at home.
"I think if the U.S. is saying we endorse what Calderon is doing, we support what he is doing to fight crime, to support the economy, those are all probably good things from his perspective," said Eric Olson, a senior adviser at the Woodrow Wilson International Center's Mexico Institute in Washington.
Mr. Obama is hugely popular in Mexico.
Opponents say the Arizona measure encourages racial discrimination and Mr. Obama has condemned it. His administration has threatened to sue and said the issue underscores the need for a major immigration policy overhaul.
But opinion polls show the statute is popular with Americans, and other states have expressed interest in passing similar laws.