Updated

The International Criminal Court said Monday it has been in contact with Libyan army officers to gather information about civilian deaths during the uprising against Moammar Gadhafi's regime, and appealed for video footage to help investigate possible crimes against humanity.

Chief Prosecutor Luis Moreno-Ocampo said he hoped to decide within days whether to open a formal investigation that could lead to indictments against those responsible, and had formed a team to begin collecting information.

"Information suggests that forces loyal to President Moammar Gadhafi are attacking civilians in Libya. This could constitute crimes against humanity and must stop," the Argentinian prosecutor said.

"There will be no impunity for leaders involved in commission of crimes," he said.

Moreno-Ocampo said his investigators had been in touch with Libyan officials and army officers to understand the command structure in Libya, which could help determine who might be subject to prosecution. He did not elaborate on who his office had contacted or how.

The U.N. Security Council instructed the court in The Hague to decide whether crimes had been committed in Libya. It also imposed sanctions on the country, urged nations to freeze the assets of Gadhafi and members of his family and imposed a travel ban on the family and close associates.

It was only the second time the U.N. body had asked the world's first permanent war crimes tribunal to intercede in a conflict, following its 2005 request to probe mass killings in Darfur in western Sudan.

That investigation led to an indictment for genocide of President Omar al-Bashir. The Sudanese leader has rejected the charges and refused to surrender to the court, underscoring one of the key challenges facing international war crimes prosecutions — the inability to have suspects arrested because tribunals do not have their own police forces.

Moreno-Ocampo said his preliminary probe must establish whether crimes in the court's jurisdiction were committed, whether perpetrators could be prosecuted in Libya, whether crimes are serious enough to merit a case in The Hague and whether it is "in the interests of justice" to prosecute them.

"If people were in the square and they were attacked by tanks or airplanes or soldiers and people were killed in a systematic way, this is a crime against humanity. If we prove that, we will present the case," he said.

The Security Council called on Moreno-Ocampo to report back to the council in two months.

U.N. Secretary General Ban Ki-moon cited reports that perhaps 1,000 have died amid the popular uprising and the government's violent crackdown on Gadhafi critics.

The prosecutor praised the international community's swift reaction to the turmoil in Libya, saying he also is in touch with the Arab League and African Union, two organizations he has clashed with in the past over his investigations in Kenya and Sudan.

The court has no investigators in Libya and Moreno-Ocampo said he could carry out an investigation without sending staff there. His Darfur investigation was conducted without Sudanese officials granting permission to visit the region.

Moreno-Ocampo also appealed for "footage and images to confirm alleged crimes." In the early days of fighting in Libya, many of the images of the crackdown were taken by the protesters themselves, often grainy recordings on mobile phones.

While he conceded it would be a challenge to collect evidence while the conflict is still raging and to protect potential witnesses, Moreno-Ocampo said, "there's plenty of public information, so we are confirming some points and I hope we can move very fast."

Most existing cases at the court have not been so swift.

The tribunal's first trial, against Congolese warlord Thomas Lubanga who is accused of recruiting child soldiers, has been beset by delays and clashes between judges and prosecutors.

The proceedings were twice halted and judges rebuked prosecutors for withholding evidence, saying it could deprive him of a fair trial. Arrested five years ago, his trial is still going on.

Another three Congolese suspects also are on trial, including former Vice President Jean-Pierre Bemba, who is charged with atrocities in the Central African Republic.