WASHINGTON, April 24 -- In the heart of the US capital, a fence stands adorned with 20,000 teddy bears to represent the Ukrainian children who, according to Kyiv, have been abducted by invading Russia, as war rages on.

Activists held a gathering of US lawmakers yesterday at the sombre display located a stone's throw from the Capitol, with a simple plea: "Bring Them Home."

"When you see the scale... you then start to understand how terrifying this is, and that all this time, while we are waiting for some kind of negotiations, there is children's life at stake," said Mariia Hlyten, a 24-year-old Ukrainian activist.

"They have to be returned immediately, as soon as possible."

Congressmen Richard Blumenthal, Jamie Raskin and Michael McCau...