Throughout the protracted conflict in Northern Ireland (1960s-1998), the Provisional IRA developed a series of improvised mortars to attack British Army and Royal Ulster Constabulary (RUC) security bases. The organisation also purchased both light and heavy machine guns in order to hamper the British Army supply of border bases by helicopter. The IRA fitted vehicles, specially vans and trucks, with both type of weapons. Vans, trucks and tractors were modified to transport concealed improvised mortars to a launch area near the intended target and fire them, while light and heavy trucks were employed as firing platforms mounting machine guns, particularly M60s and DShKs. Improvised armoured vehicles and heavy equipment were also used to penetrate fortified security bases. The IRA vehicles were often disguised as belonging to civilian companies or even government agencies.