The International Criminal Court convicted the little known militia leader Thomas Lubanga Dyilo of using child soldiers in the Democratic Republic of Congo Wednesday. But critics noted that deadlock among world powers means the ICC is not even investigating daily tales of atrocity emanating from the Syria of President Bashar Al-Assad.

Another sitting head of state, Sudan's Omar Al-Bashir, cocks a snook at a three-year-old arrest warrant. And big states including the United States, Russia and China, none of which accepts the jurisdiction of the Court, trade charges of hypocrisy over their own behaviour in places like Iraq, Chechnya or Tibet.

Navi Pillay, a former ICC judge who now heads the UN human rights agency, hailed the first verdict in the court's 10-year existence as a "major milestone in the fight against impunity".

But her own agency has been forced to lock away evidence it has gathered against Syrian officials of crimes against humanity during the past year's crackdown on anti-Assad protests, due to the international stalemate in the UN Security Council, the only body empowered to order an ICC investigation on Syria.

Many in Congo, and on a continent long ravaged by men like him, welcomed that Lubanga, 51, had been brought to book for snatching boys and girls aged under 15 and forcing them to fight in a five-year jungle war that killed some 60,000 people in the east of the country around the turn of the century.

He will be sentenced only later, and has a month to appeal.

But some Africans grumbled the ICC does too little to hold to account others elsewhere, or is succeeding only in hitting the small fry, or losers like former Ivory Coast president Laurent Gbagbo, who now sits in custody on the Dutch coast.

Watched among others by actress and human rights campaigner Angelina Jolie, Lubanga sat impassively in the dock in white robes and cap, having denied all charges. Yet one of his co-accused still serves as general in the Congolese army - a vivid reminder of the political limitations on the court.

It was set up to provide a permanent forum after ad hoc tribunals, inspired by the Nuremberg trials of Nazi leaders, were used to prosecute those responsible for war crimes in the former Yugoslavia and for the Rwandan genocide of the 1990s.

"Two decades ago, international justice was an empty threat," Pillay said. "Since then a great deal has been achieved and the coming of age of the ICC is of immense importance in the struggle to bring justice and deter further crimes."

But the ICC can work only with the assent of political leaders: "Is it going to give pause to Bashar Al-Assad?" asked Reed Brody, counsel for Human Rights Watch, of the conviction of a man he called a "small fish" in Africa. "I don't think so."

"Have we seen atrocities fall off in the world? We only have to look at Syria to know it's not the case," he said, noting how veto-wielding Russia and China were blocking Western and Arab efforts to have the Security Council act against Assad.

That is the only way to initiate a prosecution, since Syria, like Russia and China but also the United States, is not a party to the Rome Statute, which created the Court in July 2002. While most countries have signed up, the ICC's big opponents see it as a threat to national sovereignty and to their global interests.

"It's not the fault of the ICC," said Brody, who established a reputation as a scourge of dictators during efforts to try Chile's Augusto Pinochet and Haiti's "Baby Doc" Duvalier. "It's the fault of the Security Council and of the world order ... the international justice system does not operate in a vacuum."

While welcoming the verdict against Lubanga, which may help set a precedent for other cases involving the recruitment of child soldiers, he added: "Those countries with political power and their allies have been shielded from the court."

While there has been talk among international jurists of trying to mount a case against Assad other Syrian officials in the national courts of, for example Spain, Britain or Belgium, which have asserted global jurisdiction for crimes against humanity, there seems little immediate prospect of that.

Assad and his aides also run the risk that defeat could bring prosecution at home, as happened to Saddam Hussein in US-occupied Iraq and faces the son of Muammar Gaddafi, Saif Al-Islam, following his capture last year in Libya.

At The Hague on Wednesday, ICC Presiding Judge Adrian Fulford said in reading the court's historic first judgment: "The chamber concludes that the prosecution has proved beyond reasonable doubt that Mr. Thomas Lubanga Dyilo is guilty of conscripting and enlisting children under the age of 15 years."

He was detained six years ago and faced three counts of war crimes. He could face up to life imprisonment.

The three-judge panel said children were forced into camps in the Ituri region, where they were placed under harsh training regimes and brutally punished. Soldiers and army commanders under Lubanga's authority used girls as domestic workers and subjected them to rape and sexual violence, they said.

"The accused and his co-perpetrators agreed to, and participated in, a common plan to build an army for the purpose of establishing and maintaining political and military control over Ituri," they said. "This resulted in the conscription and enlistment of boys and girls under the age of 15."

Congolese Justice Minister Luzolo Bambi Lessa hailed the "historic" verdict and said the fact his country has more people facing justice at the ICC than any other showed critics of the Kinshasa government that it was serious about ending abuses.

In the eastern Congolese city of Goma, Sharanjeet Parmar of the human rights group the International Center for Transitional Justice, said: "The result is important for the ICC as Lubanga is its first trial. But more importantly for the DRC in terms of fighting the culture of impunity, because very few people who're accused of war crimes are brought to justice."

Local people, she added, were eager now to see some form of reparation made for their suffering - as well as Bosco Ntaganda, the general indicted along with Lubanga, handed over to the ICC.

"His continued liberty is actually a threat to peace," Parmar said. "It's important that he's handed over in light of the fact he is still implicated in ongoing violations."

Elsewhere in Africa, there was a welcome for a thug getting his just deserts, but some irritation that others, ranging from Israel and the United States, to Sri Lanka or Syria, had not felt the breath of ICC prosecutors at their heels.

At Bottom Mango Junction in Freetown, capital of Sierra Leone, people with memories of the civil war in their country - for which some are being tried in an internationally-backed local court - praised the ICC's concern for Africans, who have suffered more than most from the depredations of warlords.

"The ICC is treating Africa fairly," said Brian Ansumana, who sells diesel oil. "Because these warlords, they are using children in war, giving them guns, drugs. The ICC is in place to see that those crimes are not committed in Africa."