Boko Haram's leader, Abubakar Shekau, has said the 219 schoolgirls kidnapped from the remote town of Chibok in Nigeria's northeast in April have converted to Islam and been married off.

Shekau made the remarks in a video obtained by the AFP news agency on Friday.

"Don't you know the over 200 Chibok schoolgirls have converted to Islam? They have now memorised two chapters of the Koran," he said.

"We have married them off. They are in their marital homes," he added.

In a previous statement the group's leader threatened to sell the girls as slave brides and also suggested that he would be prepared to release them in exchange for Boko Haram prisoners.

Ceasefire claims denied

Shekau also said the group was holding a German national and denied they had agreed to a ceasefire, describing the Nigerian government statement as a lie. He also appeareed to rule out future talks.

The video comes after a surprise Nigerian military and presidency announcement on October 17 that a peace deal had been reached with the group.

A senior presidential aide to President Goodluck Jonathan also said that an agreement had been reached to free the schoolgirls, whose abduction sparked a global campaign for their release.

There was immediate scepticism about both claims because of previous assertions of ceasefires and the identity of the purported Boko Haram envoy at the supposed talks, Danladi Ahmadu.

Allen Manasseh, an activist working with the campaign to free the girls captured by Boko Haram, said to Al Jazeera live from Abuja on Saturday.

"This is another moment of shattered hope to our people," he said.

"We have received the cease fire announcement with caution because of the previous arrangements that did not translate to having these girls released, and today we questioned the issue of the cease fire because of the way the Nigerian government had handled it," Manasseh added.

Fresh attacks

Violence and fresh kidnappings have continued unabated since the announcement, including a triple bombing of a bus station in the northern city of Gombe on Friday that killed at least eight.

Nigeria's government maintains that talks are ongoing in the Chadian capital, Ndjamena.

But Shekau, dressed in military fatigues and boots with a black turban, and flanked by 15 armed fighters, said: "We have not made ceasefire with anyone..."

"We did not negotiate with anyone... It's a lie. It's a lie. We will not negotiate. What is our business with negotiation? Allah said we should not."

He also said he did not know Danladi.

There was no indication of when or where the video was shot but it was obtained through the same channels as previous communications from the group.

The New York-based Human Rights Watch said in a report this week that Boko Haram was holding upwards of 500 women and young girls and that forced marriage was commonplace in the group's camps.