Blast Nazi ShipsPanicky Residents of Norway's Capital Flee for Lives; Sea, Air Duels Rage Off CoastSTOCKHOLM, April 10 AP Panic-stricken residents of Oslo, the Norwegian capital occupied but Tuesday by the Germans, fled by every available conveyance Wednesday after British warships were reported to have forced the rocky Oslo fjord and threatened to bombard the city unless it was surrendered within a few hours by its nazi masters.The city was ordered emptied of its population at 11:15 a. m. 3: 15 a. m., M. S. T.The British, said delayed dispatches reaching here by way of the Swedish-Norwegian frontier town of Charlottenberg, threatened to start shelling the town at 1 p. m., but whether the bombardment actually took place was not known.Long Columns of RefugeesLong columns of cars, trucks and buses began taking the civilians still in Oslo from the city.The crowds at railway stations were so great it was almost impossible to push up to the gates.Mothers, with children in their arms, fainted in the crushAbout half the 250, 000 population had left before the nazis occupied the city.The entry of the British into Oslofjord was reported to have followed a long battle at the fjord entrance, in which the Germans were believed to have lost 40, 000 tons of warships, including one vessel of the Deutschland class, in contacts with both British guns and the navy and coastal artillery of the Norwegians.But this battle was only one piece of a giant jig-saw puzzle of sea action Wednesday that ranged from northern Norway at Narvik, to within sight of the Swedish shore at the juncture of Skagerrak and Kattegat.One unit of the British navy plunged into the mined Skagerrak and broke up a fleet of 10 German troop transports in a three-hour battle Wednesday night within sight of the Swedish coast, sinking two of the transports and a destroyer.