She said the terrorist group had established control in large swathes of Syria and Iraq, and "must be dealt with."
"We will not allow this to go unanswered," she said in a speech to parliament just before midnight (0600 GMT Friday).
She said Germany was ready to stand up to IS and warned against complacency.
"We are in a war against IS," she said. "We must fight against it in any means possible."
Her comments came as a German government source said IS fighters were still controlling significant swaths of territory in Syria and Iraq.
"In the coming hours, we will find out whether IS is able to hold on to much of its territory in Iraq," the source told AFP.
"If it does not, we will see if we can do much to stop it with our air strikes."
The Syrian Observatory for Human Rights, a British-based group monitoring the conflict, cited residents of northern Raqqa, IS' stronghold in Syria, as saying the jihadists were still holding some areas.
Meanwhile, German officials have confirmed the death of a German citizen who was killed in Syria, but said it was not clear if he had been killed or wounded.
Merkel offered her condolences to the family of the man who died and described him as a "dear friend".
"He was a remarkable, heroic and brilliant man and one who gave the best of himself," she said.
The celebration is to honour the German pilot who flew the plane into the tower of the German aircraft carrier in June.
In June, German Chancellor Angela Merkel came under fire for comparing IS fighters to children while speaking at a conference in Berlin.
Rescuers trying to reach the plane said it was stuck in the water and aloft when it entered the water.
German officials had hoped the attack wouldn't prove too difficult, and planned to use rope or boats to break it in half. The plane had broken apart during the rush.
Merkel said she was confident about the German air force's plan to use the Tornado jet against IS fighters, despite the warnings from her top military officers that it was not the best aircraft to use against IS.
"Whilst our air force is somewhat short of resources, it must be prepared as we cannot afford to waste any potential opportunities," she said at the time.
The German air force's Tornado jets, which are equipped with flak wings and other necessary devices, were ordered to use against IS by Mariano Rajoy, the Spanish prime minister.
Rajoy had earlier warned that Spain could face a "decades of isolation" if it continues to support the jihadists and imposed extra controls on the purchase of arms and ammunition.
The Moroccan authorities have ordered the removal of IS flags from public buildings.
A spokesman for the Moroccan embassy in Berlin said Tunisian-born Tunisian imam Ibrahim al-Assaad was the spiritual leader of the Muslim community in Germany.
Rajoy's spokesman said in a news release that "the Spanish government is in full agreement with the measures taken by the Moroccan government to protect the rights of the Spanish citizens in Algeria, Morocco and Tunisia."
Rajoy said he would be opening an official diplomatic channel with Spain, the European Union and the United States in a few days to discuss the situation in Spain.
He promised that Madrid would "not forget" the Spanish people who have borne the brunt of the conflict in the Middle East.
Rajoy said that after spending the last six months in a state of national mourning, he was ready to fight again.
"I will fight again," he said.<|endoftext|>Sanders: 'If you work for a living, you should be able to afford to eat properly'
I'm bracing myself for a lesson in vegan cooking; I'm a vegetarian, after all. But I did my research and found the following cookbooks:
Coconut Milk Cream Pie Recipe
1 (18 ounce) can sweetened coconut milk
2 cups all-purpose flour
2 cups white sugar
1 (3 ounce) package instant coconut cream pudding mix
1 teaspoon vanilla extract
1 (8 ounce) package cream cheese, softened
1 (8 ounce) package cream cheese, softened
1 (8 ounce) can evaporated milk
1/2 cup shredded Cheddar cheese
1 cup sliced Swiss cheese
Preheat oven to 350 degrees F (175 degrees C). In a medium-size bowl, mix together coconut milk and flour. Stir in the sugar, pudding mix, and vanilla extract. Press the mixture evenly into the bottom of a 9 inch round pie pan.
Bake for 15 minutes in the preheated oven, then remove from the oven and sprinkle the cream cheese, cream cheese, evaporated milk, C