After meeting top Latvian state officials, including Latvian President Andris Berzins and Prime Minister Laimdota Straujuma, Merkel said NATO's defensive pacts were "not just words", Xinhua reported.
"If any member state is threatened, real action would follow," the chancellor said, adding, "article 5 is not just theoretical. It is an agreement that must be enforced if need be -- we must be prepared for this."
Merkel said she supported more efficient defence infrastructure instead of long-term deployment of troops that would be able to react without delay.
Addressing Russian sanctions, the chancellor said in a "non-standard situation, the European Union could review the possibility of support packages for goods producers in wake of the counter-sanctions announced by Russia".
Merkel also noted that EU sanctions were inevitable and were aimed at expressing its clear position on the situation in Ukraine. She said German pork producers had been affected by Russia's sanctions since the beginning of this year.