Police in Northern Ireland are investigating reports of an explosive device outside the west Belfast home of the brother of the murdered solicitor Pat Finucane.

Sinn Féin said a crude pipe device had been thrown at a house belonging to Martin Finucane, who is also the uncle of the party’s newly elected North Belfast MP, John Finucane. A front window of the house was reportedly smashed.

The attack and subsequent security alert in the Glenties Drive area came after Sinn Féin’s vice-president, Michelle O’Neill, and party colleague Gerry Kelly said police had warned them that dissident republicans were planning attacks on party leaders.

Paul Maskey, Sinn Féin’s West Belfast MP, said leaving a pipe bomb at the home “shows callous disregard for the Finucane family and the local community. Those behind this device have nothing to offer society.”

The MP called on anyone with any information about the attack to talk to the police.

The Police Service of Northern Ireland said: “Police are currently in attendance at a security alert in the Glenties Drive area of west Belfast following the discovery of a suspicious object outside a house in the area. No homes have been evacuated at this time.”

Relatives 4 Justice, which campaigns for people killed by mainly the security forces and loyalists during the Troubles, condemned the incident.

The group said it was “absolutely sickened that a bomb has been thrown at the home of one of our founding members”.

Pat Finucane, 39, a Belfast lawyer who represented a number of high-profile republicans, was shot dead in front of his family by loyalist gunmen at his home in 1989.

At the time of the murder, up to 29 members of the Ulster Defence Association units involved in the killing were working as agents for one or more branches of the security forces. There have been long-standing allegations that members of the security forces colluded with the solicitor’s loyalist killers.

The Pat Finucane Centre said it was shocked about the attack on one of its board members.

Political allies of two armed dissident republican groups have issued statements saying that neither the Continuity IRA nor the New IRA were targeting Sinn Féin.

Saoradh, which is politically aligned to the New IRA, rejected claims that there was a dissident republican campaign targeting Sinn Féin members or supporters. A spokesperson described the claims as “phantom threats to distract and deflect from policy changes”.

Republican Sinn Féin, political allies of the Continuity IRA, also rejected the theory that dissident republicans were preparing to attack Sinn Féin. Des Dalton, a senior RSF spokesman, said: “It’s a line they trot out anytime they are looking to galvanise support or cause a distraction.”