Chad's military has carried out a series of air strikes against Boko Haram bases in Nigeria in retaliation for twin suicide bombings this week in the Chadian capital N'Djamena that killed at least 34 people, it said in a statement late on Wednesday.
The Chadian army said the strikes had caused heavy human and material damage to six of the Islamist militants' bases. It provided no further details.
Chad has been a driving force behind a regional military campaign that has inflicted a series of defeats on Boko Haram since January, though the Islamist group has retained the capacity to carry out a wave of bombings in recent weeks.
"Our defence and security forces will hunt down without mercy these terrorist without faith nor law so that spilling the blood of Chadians will not go unpunished," said the written statement by army spokesman Colonel Azem Bermendoa.
Monday's simultaneous attacks on a police headquarters and a training school were the first of their kind in the central African nation, which has emerged as a key Western ally against Islamist groups in the Sahel.
The government, which said that four Boko Haram fighters were among the 27 dead, has detained at least five suspects in connection with attacks.
No one has claimed responsibility for the attacks.
The government has also announced a raft of measures to tighten security in the capital which serves as the headquarters for a 3,000-strong French military mission, including a ban on head-to-toe burqas and turbans.
A Reuters correspondent in N'Djamena said he had not witnessed any women wearing burqas on the streets since Wednesday's announcement. However, authorities had not yet followed through on a pledge to remove burqas from sale in the market.