EVENTS

CHECHEN DEFENDERS PUSH RUSSIANS BACK Grozny's Chechen defenders kept their grip on the heart of Grozny Jan. 3 after driving Russian attackers out of the center of the besieged capital. Burned tanks littered the streets. Chechen forces appeared to hold most of the southern part of the sprawling city as well. North of the center, there was heavy fighting. Morale appeared high among the Chechen fighters. Russian forces trying to take Grozny were pushed out of the city center Jan. 3 by badly outnumbered, outgunned Chechens who have fought them every step of the way. The Russian government said its troops were ``regrouping'' and reinforcements were on the way. The Chechens, mostly lightly armed volunteers, have fought the Russians street by street, hanging on to the Presidential Palace in the heart of the city despite pounding by Russian tanks. Bihac withdrawal

Croatian Serbs, who had threatened to unravel the new four-month truce across Bosnia, were withdrawing to their own territory on Jan. 3, UN officials said. The forces from Serb-held Croatia imperiled the truce by fighting on in northwestern Bosnia. They intervened in the Bihac pocket, which borders their territory in Croatia, in November when Bosnian Serbs and rebel Muslims launched an offensive in the area.

Middle East talks

Israeli Foreign Minister Shimon Peres said Jan. 3 that the killing of three Palestinian policemen by Israeli troops was ``very unfortunate'' but should not block peace talks with the PLO. Mr. Peres met with Egyptian President Hosni Mubarak and addressed a business group in Cairo before his talks with the chief Palestine Liberation Organization negotiator, Nabil Shaath.

Boston NAACP woes

The federal government has foreclosed on the office of the nation's oldest NAACP chapter. The Boston chapter is 16 months behind on its mortgage payments, and heat and water to the office have been turned off. The organization is being run from the home of chapter president Jack Robinson. Meetings are being held at members' homes and a community college.

Sri Lankan cease-fire

Government and Tamil rebel negotiators Jan. 3 agreed to a cease-fire to end Sri Lanka's 11-year civil war. The rebels also freed four policemen held more than four years. The accord came in day-long talks in northern Sri Lanka. It was the first cease-fire in five years.

Foreign workers

The Clinton administration is cracking down on companies that hire foreign professionals in temporary jobs as a way to drive down US labor costs. US regulations allow employers to hire foreign nationals in skilled professions where Americans are in short supply, such as computer programming, medicine, and some teaching and engineering fields. The Labor Department said it is reducing from six to three years the duration of the work permits.

Exploding star theory

A mass extinction on Earth 225 million years ago may have been caused by an exploding star that zapped the planet with radiation and stripped away the protective ozone layer, a scientist says. An explosion of a supernova within 30 light years of Earth would bathe the planet's upper atmosphere with powerful gamma- and cosmic-ray radiation that would destroy the ozone layer, says David Schramm, an astrophysicist at the University of Chicago.