West Africa's regional bloc said Tuesday it will impose sanctions on those it finds responsible for allowing an attack on Mali's president at his office.

Interim President Dioncounda Traore suffered a head wound after Monday's attack by protesters and was taken to a hospital. Traore was released from the hospital a few hours later.

The Economic Community of West African States, or ECOWAS, in a statement said it was launching an investigation, and that protests leading to the attack must have been organized by forces wanting to disrupt a return to constitutional rule in Mali. The bloc expressed surprise that an attack could have taken place at the presidential palace where security is usually tight.

"ECOWAS strongly condemns this attack which it considers an act of defiance towards its decisions," the president of the ECOWAS Commission Kadre Desire Ouedraogo said Tuesday.

The bloc struck a deal over the weekend with Mali's junta to allow the interim president to stay on in office for 12 months until new elections can be held. The junta had previously opposed the automatic extension of the president's mandate and had asked for a national convention to choose who should be president of Mali.

The protests in Bamako on Monday were organized by groups angry about the ECOWAS deal and the extension of Traore's mandate.

U.N. Secretary-General Ban Ki-moon condemned the attack on Traore and urged the Malian military and security institutions "to fulfil their primary function of protecting the State and its legitimate interim authorities," U.N. spokesman Martin Nesirky said.

Ban "underscores the need for those responsible for the attack to be held accountable ... (and) urges all actors in Mali to refrain from any actions that may undermine the transitional process and further endanger peace and stability in the country," Nesirky said.

An alliance of Mali's main political parties said in a statement late Monday that the attack on Traore was the result of a campaign of hate run for many weeks by certain radio stations, politicians and civil society actors.

The Front for the Protection of Democracy and the State called on the government to investigate the attack and bring those who carried it out to justice. The group said that the responsibility of those in charge of public security and the protection of public figures had also been called into question.

"Failures in the chain of responsibility should also be identified and rigorously punished," the FDR statement said.

An Associated Press reporter present at the presidential palace on Monday saw some soldiers who were supposed to be guarding the building wave protesters through the gates.

Another local reporter said that soldiers had shown protesters the way to the president's office.

On Monday night the junta released a statement condemning the attack on the president but did not explicitly ask for protests against the ECOWAS deal to stop. The junta statement made no call for an investigation into the attack.

Military officers toppled Mali's democratically elected president on March 21. West African leaders have been pressuring them to return the country to civilian rule ever since.

On Tuesday the chief ECOWAS negotiator in the Malian crisis, the foreign minister of Burkina Faso, told Radio France International that it was likely that more general sanctions would be imposed again on Mali given how the events of Monday had once again disrupted the process of returning the country to civilian rule.

"I'm afraid that now there is only one path, that of sanctions and coercion," Djibrill Bassole said.


Associated Press writer Edith M. Lederer at the United Nations contributed to this report.