Neither Jos nor Kano has been the focus of recent attacks by Boko Haram. But the deadly blasts occurred amid unprecedented international attention and growing pressure on the group, and could be a signal to the world that it is not backing down. Last Saturday, a summit meeting in Paris brought together Nigeria and neighboring nations to discuss the Boko Haram threat and culminated with a vow of military cooperation.

Earlier, spurred by international outrage over the girls, who were taken from their remote rural school in mid-April by the Islamist extremist group, the United States, Britain, France and Israel pledged to provide military aid — including personnel, intelligence-gathering and aircraft overflights — to assist Nigeria in rescuing them.

An Islamist militant attack on Jos could have particularly dire consequences as it has been a flash point of Christian-Muslim tensions for years. The sprawling city lies at the edge of the Muslim-majority northern half of the country. Already on Tuesday evening, there were reports of reprisal attacks in Jos.

Apart from a defiant and mocking video message from Boko Haram’s presumed leader last week, the bomb blasts — if indeed they are the work of the group — seem designed to demonstrate to the Nigerian government and its allies that the Islamist rebel group was unimpressed by the condemnations and vows to strike it down.

By continuing to seek out targets like markets, city centers, schools and bus stations, the group seemed keen on showing that it could sow terror among civilians wherever and whenever it wants. A deadly blast here the day before the girls were abducted killed at least 75; 300 people were also killed in a village near the border of Cameroon two weeks ago.