Kidnappers threatened in a video to execute a German woman and her 20-year-old son unless Germany pulls its soldiers out of Afghanistan. Kidnappers said if Germany didn't concede to their demands by Tuesday, the hostages would be killed.

The welfare of the hostages remains unknown.

"We refuse to be blackmailed by people who do horrible things to others," Merkel said Monday evening in Rome, where she had met with Italian Prime Minister Romano Prodi.

The government will continue to push for the release of the hostages, Merkel said.

On Feb. 6, a militant Islamist group in Iraq kidnapped Hannelore Krause, 61, who is married to an Iraqi doctor, and her son Sinan, who works at the Iraqi foreign ministry. The kidnappers, who call themselves Kataeb Siham al-Haq (Righteous Arrows Battalions), threatened to kill the two if Germany didn't meet their demands.

Germany won't pull troops from Afghanistan

Germany has nearly 3,000 troops in northern Afghanistan as part of the NATO-led International Security Assistance Force. The Bundestag, Germany's lower house of parliament, recently agreed to deploy six Tornado reconnaissance warplanes to the region.

Earlier Monday, Merkel met with Afghan President Hamid Karzai in Berlin. The two talked about the hostage situation and Merkel promised Germany would not abandon Afghanistan because of threats from terrorists.

"Naturally, given the situation, we are greatly concerned," Merkel said of the kidnapping victims. "We know what our commitment to the civilian rebuilding means to the Afghan government, and we should not be blackmailed by people who are terrorists."

Italian journalist freed

A few hours before the Monday evening press conference, an Italian journalist and his interpreter were freed after being taken as a hostage in Afghanistan two weeks earlier.

Daniele Mastrogiacomo told Italian media Monday that he constantly feared execution during his two-week hostage ordeal. He was forced to watch his suspected Taliban abductors behead his Afghan chauffeur.