Zimbabwe ? President Robert Mugabe’s regime struck at his rivals Thursday only two weeks before Zimbabwe’s presidential runoff, twice detaining his challenger and jailing the No. 2 opposition leader to face treason charges.

The U.S. ambassador, meanwhile, said 20 tons of American food aid heading to impoverished Zimbabwean children had been seized by authorities last week and given to Mugabe supporters at a rally.

The repeated detentions, coupled with Western accusations that Mugabe’s regime is using food as a weapon, dramatically demonstrate the obstacles to the campaign thrown up by the longtime leader.

“This is a government that is taking tremendous and, frankly, awful strides to maintain its power, that is increasingly abusing its own citizens and has raised, or should I say lowered, the bar to a level that we rarely see,” State Department spokesman Gonzalo Gallegos said in Washington.

White House press secretary Dana Perino, traveling in Europe with President Bush, said the U.N. Security Council should quickly take up the Zimbabwe crisis “to prevent further deterioration of the region’s humanitarian and security situation.”