Calderón, who is on his first trip to Europe, held talks with Merkel, as well as German business leaders as part of efforts to attract investment to Mexico.

"A state where all people can live in the knowledge that they are secure and where they can trust in the justice system is the kind of state that will attract investment," Calderón said, pledging to support such efforts in Mexico.

"Mexico is a nation that believes in human rights and respects human rights," Calderón said.

SPECIAL INVITATION

Merkel, whose nation currently holds the presidencies of both the European Union and the G-8 group of industrial nations, said she had invited Calderón - and he had accepted - to attend the July G-8 summit as an observer.

Both leaders also pledged to further bilateral cooperation in the areas of economics, trade and the environment.

"Germany is Mexico´s most important economic partner within the European Union," Merkel said.

Earlier in the day, 18 demonstrators skirted security measures at German President Horst Koehler´s residence to unfurl a banner with the spray-painted message "No More Murder Mexico: Out of Oaxaca" before being apprehended by federal police.

The incident occurred about 12:30, some 20 minutes before Calderón arrived at the residence to meet with Koehler.

18 PROTESTERS ARRESTED

All 18 were taken into temporary custody and faced possible charges of violating the country´s right-to-assembly laws, said federal police spokeswoman Stefanie Kaufmann.

Berlin was Calderón´s first stop on a six-day tour of Europe, where he planned to meet with global heavyweights at the World Economic Forum in Davos, Switzerland, and encourage foreign investment in Mexico.