By MICHAEL SCHWIRTZ
MOSCOW - As Belarussian diplomats scrambled on Wednesday to assuage European concerns about the sweeping crackdown on dissent in their country, the authorities in Belarus were stepping up their campaign against the family of a former presidential candidate whose three-year-old son they have threatened to seize.
The security services conducted a search of the home of the former candidate, Andrei Sannikov, as well as the apartment of his wife's mother, who has been caring for the child, Danil.
Both Mr. Sannikov and his wife, Irina Khalip, a journalist, were arrested following a brutal police assault on demonstrators protesting the results of a presidential election in Belarus last month. The government has warned that it could take custody of Danil if his grandmother is deemed unfit to care for him. Relatives, however, believe it is an effort to intimidate the boy's parents.
The grandmother, Lyutsina Khalip, said she signed an agreement promising not to reveal details about Wednesday's search. "I can't say anything or I risk making it worse," she said by telephone.
The searches are part of a broader clampdown on opponents of President Aleksandr G. Lukashenko. Almost daily, the security services, still called the K.G.B. in this former Soviet republic, have been conducting raids on the offices and homes of people linked to the opposition, interrogating them for hours and confiscating computers and other potentially compromising materials, human rights groups say. Independent media outlets have been shut down, and hundreds were detained. Seven of the nine opposition candidates who ran against Mr. Lukashenko in elections were arrested, and four of them remain in custody.
Citing the continuing campaign, European leaders rebuffed a last ditch diplomatic effort by Belarus on Wednesday, all but dismissing the possibility that relations between the West and the former Soviet republic could be salvaged.
The foreign minister of Belarus, Sergei Martynov, had traveled to Brussels for meetings with European leaders in an apparent attempt to counter what the government of Belarus has called a distorted perception of events in the country.
The European Union has threatened to impose sanctions, including a travel ban on Belarussian leaders, in response to the post-election crackdown. Mr. Lukashenko won the election with almost 80 percent of the vote, though independent observers said the ballot counting was rigged.
In a meeting with Mr. Martynov on Wednesday, Catherine Ashton, the European Union foreign policy chief, reiterated the condemnation and warned of "appropriate measures" if the government failed to quickly release opposition leaders, journalists and others jailed for organizing and participating in last month's rally, according to a statement on the European Union Web site.
The United States, which has had sanctions in place against the government of Belarus for several years, has also denounced the authorities' actions.
More than 600 people were arrested when police violently dispersed the anti-government rally in Minsk, the Belarusian capital, on Dec. 19. About 30 people, including Mr. Sannikov and at least three other former presidential candidates, face up to 15 years in prison for their roles in the protest.
The heavy-handed response has been met with shock and embarrassment in the European Union, where leaders have sought to cultivate a more pragmatic relationship with Mr. Lukashenko over the past several years. In response to promises of democratic reform, Mr. Lukashenko was offered economic incentives, including about $3.5 billion in aid ahead of the elections.
European leaders now say the approach was misguided.
"We know very well that we should change our policy towards Belarus," Jerzy Buzek, the president of the European Parliament, told visiting Belarusian opposition leaders in Brussels on Wednesday.
In a hearing on Belarus later in the day, European lawmakers called for the swift imposition of sanctions against Mr. Lukashenko and his government, though they warned against isolating the country completely.
"The people of Belarus are welcome in the European family of free and democratic nations," Mr. Buzek said. He and others suggested easing visa restrictions for citizens of Belarus seeking to travel to the European Union, as well as providing scholarships for Belarussian students to attend European universities. A final decision on these and other measures is expected at the end of the month.
Visiting opposition leaders from Belarus made it clear that they were dependent on quick European intervention to halt the campaign against them.
"We need strict actions, we need concrete steps," said Eva Neklyaeva, whose father, Vladimir Neklyaev, a former opposition candidate, was beaten unconscious then jailed following last month's elections. "We need you to understand that you have a key to my father's prison."