Security forces found the bodies of 25 hostages on Sunday as they combed a desert gas plant after a deadly stand-off with Islamists, and witnesses said nine Japanese captives had been executed.

Citing security sources, Anis Rahmani of private television channel Ennahar told Agence France Presse the army discovered "the bodies of 25 hostages" as they secured the sprawling In Amenas Sahara site.

French Foreign Minister Laurent Fabius said Sunday that Russia had offered to help transport French troops and supplies to Mali and that Canada was to help to bring African troops to the country.

Asked on Europe 1 radio about how African troops would be transported, Fabius said "there is transportation that will be partly by the Africans themselves, partly by the Europeans and partly by the Canadians."

Colombian President Juan Manuel Santos has warned the country's leftist rebels against resuming violent guerrilla operations, saying the army and police were ready to respond to their attacks.

The warning came as a unilateral ceasefire announced by the Revolutionary Armed Forces of Colombia (FARC) in November to facilitate peace talks with the government was set to expire on Sunday.

A total of three British nationals are confirmed dead in the Algerian hostage crisis and a further three, plus a British resident, are believed to be dead, Prime Minister David Cameron said on Sunday.

"I spoke to the Algerian prime minister yesterday and it is now clear that this appalling terrorist incident in Algeria is now over," he said in a statement.

U.S. President Barack Obama said Saturday that blame for deaths stemming from a hostage crisis in Algeria lay with the "terrorists" who had earlier taken foreigners captive at a remote gas plant.

The remarks were the president's first direct comments about the protracted hostage crisis. His statement was released several hours after Algerian troops stormed the gas plant to end a situation that had began four days earlier.

Police and army troops squared off with presumed hitmen working for drug traffickers in two deadly incidents in Mexico that left 11 gunmen dead, authorities said Saturday.

In Puente Nacional, in the eastern state of Veracruz, armed men attacked army troops who responded, killing six of the gunmen.

A Japanese engineering firm said Sunday that 10 of its Japanese and seven of its foreign workers remained unaccounted for at an Algerian gas plant seized by Islamist militants, adding the situation was "grave".

The Malaysian Foreign Ministry, quoting the firm, JGC Corp., said that two of its nationals were among the seven unaccounted for, and there was a "worrying possibility" that one of them was dead. The other three Malaysians who had been working at the plant had been confirmed safe.

The apparent leader of a commando group that took hundreds of gas workers hostage in Algeria warned in a recording broadcast Saturday that he would blow them up if the army got too close.

In the audio recording, broadcast by the Mauritanian news agency ANI, Al-Mulathameen Brigade commander Abdul Rahman al-Nigeri of Niger spoke late Thursday as the Algerian military surrounded his fighters' position at a BP oil plant deep in the Sahara desert at In Amenas.

Bulgaria's veteran Turkish minority party leader Ahmed Dogan resigned as expected Saturday, but not before he foiled a dramatic attack by a man armed with a gas pistol at his party's national conference in Sofia.

Dogan was addressing delegates of his Movement for Rights and Freedoms (MRF) party when a tall man in black leapt onto the stage, rushed to his podium and pointed the non-lethal weapon at his head, video footage showed.

West African leaders Saturday sought urgent U.N. aid for a regional force to fight Islamists in Mali as President Francois Hollande said French troops would remain as long as needed to stamp out "terrorism".

The emergency summit of the Economic Community of West African States (ECOWAS) regional bloc also called on member states and Chad, which has pledged 2,000 troops, to put words into action without haste.