The town fell to the Tigrean rebels shortly after they ended a long cease-fire with an offensive in August.
Two weeks ago Palestinian militant factions, including Hamas, sharply stepped up the rocket fire from across the border, ending a tenuous six-month cease-fire.
The attack, which ended a 17-month cease-fire, raises more political uncertainty for Britain's troubled Conservative Government.
Sandinista officials say that the strategy included the government's dramatic decision on Nov. 1 to end a 19-month-old cease-fire with contra units inside Nicaragua.
The group said attacks by its rival, the Kurdistan Democratic Party, followed, ending a week-long cease-fire.
The shooting ended a three-day cease-fire of sorts by the sniper, if indeed the woman proves to be his victim.
The peace in Northern Ireland suffered a setback last month when bombs ended a 17-month cease-fire.
The separatists have taken up arms again, especially in the southeast of the country, ending a six-year cease-fire with the government.
Hours after the killings, the Government announced it was ending a 10-day cease-fire that began on Saturday.
The two leaders would be renewing top-level talks that halted in August, during the violence that ended a previous Palestinian cease-fire.