Two men face further questioning in connection with a series of explosions near mosques in the West Midlands.

The pair - Ukrainian men aged 25 and 22 - were arrested under anti-terror laws on Thursday in Small Heath, Birmingham, in relation to recent blasts close to mosques in Walsall and Tipton. They are being held on suspicion of being involved in the commission, preparation or instigation of an act of terrorism.

The arrests came after the "seat of an explosion and debris" were found on a roundabout near the Wolverhampton Central Mosque on Thursday night. Police believe the debris came from a device that exploded on the Fiveways roundabout at about 9.15am on June 28.

The mosque was evacuated after the discovery and army bomb disposal experts searched land in and around the building on Waterloo Road. The device, details of which have not yet been released, is believed to have been planted in the early hours of June 28 or on the previous night.

West Midlands Police received reports about a "loud bang" and "a puff of smoke" that day, but the location of the explosion was not discovered until specialist teams came to investigate on Thursday. Assistant Chief Constable Marcus Beale appealed for people who may have seen anyone acting suspiciously near the roundabout on the night of June 27 or the following to come forward, and said officers were studying CCTV footage from cameras around the mosque. Mr Beale said officers were regarding the incident as part of a wider terrorist investigation into explosions near two other mosques in Walsall and Tipton in recent weeks, saying yesterday that the events were "serious and worrying".

He said that over the last few days and weeks both police and representatives of the mosques "have been worried that we have had a serial bomber of mosques in the West Midlands region, and we have been taking that very seriously". Mr Beale said that his officers were doing "all we can" to bring the offenders to justice, adding: "I have no information to suggest that there are further threats to mosques in our region."

Wolverhampton Central Mosque reopened on Friday, and representative Iftikhar Ahmed said anxieties in the area would be allayed. He said: "Of course there are concerns in the community but we have faith in the police and intelligence services that the incidents are being dealt with. They already have two suspects in custody and for our community today it is work as normal."

It was reported that the two men arrested are foreign university students who were working at a software firm in Small Heath. Police have confirmed the two men were believed to have been staying in Birmingham.

On Friday bomb disposal officers and members of West Midlands Counter Terrorism Unit searched the premises of the company Delcam. The company's chief executive, Clive Martell, told the Birmingham Mail: "The two men were on work placements with us, but were not employees of the business. They are studying at a foreign university and are engineering students."

The latest incident comes after blasts near mosques in Walsall and Tipton.