They shouted "Allahu Akbar" -- "God is great" -- and opened up on the market, firing rocket-propelled grenades and tossing improvised explosive devices, witnesses said. They were kidnapped more than three weeks ago by Islamist Boko Haram militants from their boarding school in the north-eastern state of Borno. Hide Caption 19 of 19 
 
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 Britain is sending a small team of experts to complement the U.S. team, a spokesman for Prime Minister David Cameron said Wednesday. Image copyright AP 
 
 Nigeria's police have offered a $300,000 (£180,000) reward to anyone who can help locate and rescue more than 200 abducted schoolgirls. "While calling on the general public to be part of the solution to the present security challenge, the Police High Command also reassures all citizens that any information given would be treated anonymously and with utmost confidentiality," the Nigeria Police Force said in a statement. Ahmed Zanna said the gunmen arrived in a convoy of vans in Gamboru Ngala, near the border with Cameroon. Global campaign The man behind the hashtag #BringBackOurGirls echoes that sentiment. At least eight girls between the ages of 12 and 15 were snatched Sunday night from the village of Warabe by Boko Haram, villagers said. The governments of Chad and Cameroon have denied suggestions that the abducted girls may have already been smuggled over Nigeria's porous borders into their territory. Many people locked themselves up in the market when the attacks started so they got burnt in their shops," he said.
– Nigeria is apparently feeling the international pressure over its kidnapped girls, with the national police offering a $300,000 reward today for information that leads to their rescue, reports the BBC. (The move comes a day after President Obama promised that a US team would help the cause.) But Boko Haram, the group that kidnapped the girls and vows to sell them, remains as defiant and brutal as ever. A new attack in the town of Gamboru Ngala, near the border with Cameroon, massacred at least 150 villagers, reports CNN. Local media reports say militants opened fire on a crowd of people in a busy marketplace, set homes on fire, and shot residents trying to flee the flames over a span of 12 hours, reports the AP. A Nigerian senator says the death toll is "high—hundreds—but we are still awaiting details from the military authorities." (Click to read about one girl's description of how she escaped Boko Haram.)