MANILA, Nov. 27 -- The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) reported in its 11 a.m. bulletin on Thursday that Signal No. 1 remains in effect for the Kalayaan Islands as Tropical Cyclone Koto (formerly known as Verbena) strengthens into a typhoon.

Koto packs maximum sustained winds of 140 kilometers per hour (kph) near the center, and gustiness of up to 170 kph.

It was last tracked at 255 km. north of Pag-asa Island, Kalayaan, Palawan, outside the Philippine Area of Responsibility. The cyclone is moving west-northwest at 15 kph.

Strong winds continue to prevail across the Kalayaan Islands, PAGASA said.

Koto and the northeast monsoon will also bring gusty conditions reaching strong to gal...