Apartment for rent: two rooms, mandatory 24-hour Soviet security guard, hot water for 47 weeks of the year, bathroom and kitchen fixtures not included.

Americans and other foreigners based here are snatching up such offers promptly, despite rents of $1,100 a month or more.

The reason is simple. Those apartments and prices are the only options made available by a Soviet Foreign Ministry agency charged with providing housing and other services to foreign diplomats, journalists and businessmen in the Soviet capital.

Now the U.S. State Department is offering similar assistance to Soviet journalists and officials stationed in the United States. According to rules that became effective this week, a State Department agency will act as exclusive real estate brokers to the Soviet community in Washington.

The American move is the latest in a series of actions taken by the State Department's Office of Foreign Missions, created by the Reagan administration to make conditions for foreign diplomats and other official residents assigned to the United States reflect the conditions under which Americans must work in their countries.

Moscow already has complained. In a recent dispatch, Tass correspondent Oleg Polyakovsky called the new laws "discriminatory." Their purpose, he said, "is to poison the atmosphere of U.S.-Soviet relations and to undermine the agreement released between the two countries on the elimination of medium-range and short-range missiles."

Polyakovsky also griped about a newly imposed Office of Foreign Missions travel service tailor-made for Soviet and East European journalists who want to travel in the United States. Airline tickets and hotel rooms are booked for them. Polyakovsky said in a Tass dispatch that the effect on Soviet journalists is twofold: it increases travel expenses and restricts the capacity to travel.

The Soviet Foreign Ministry has long arranged trips for Moscow-based American journalists and other foreign correspondents to cities across the Soviet Union. One of that system's advantages is that hotel and airline bookings in some of the country's more remote cities and regions are often more accessible to journalists than to tourists.

Although Soviet citizens can usually travel within the U.S.S.R. without notifying authorities, foreigners cannot. The Foreign Ministry requires two days' notice before departure. The government also demands to know the license plates of cars or the arrival times of planes and trains.

In contrast, foreigners living in Poland, East Germany and other Soviet Bloc countries are free to travel domestically without submitting such details.

At least one-third of the Soviet Union is off-limits to foreigners, including most of the major industrial cities and rural areas in Siberia. The United States, in response, has closed off portions of the country to the Soviets, especially areas heavily involved in computer and aerospace research, including much of Texas and California's "Silicon Valley." Poles, East Germans and other East Europeans are allowed access to such areas, however.

The requirement that Soviet journalists go through the State Department in their search for housing in Washington came shortly after Moscow suddenly raised the rent charged for foreigners in Moscow.

Foreigners pay much higher rents than those charged their Soviet neighbors. In a housing compound designated for foreigners, for example, an apartment with one medium-sized bedroom and a combined living and dining room now costs $1,135 a month, an increase of $105 since last month. For a similarly sized apartment, a Soviet renter pays $24.

Apartments designated for foreigners in Moscow often come without basic fixtures, and tenants are left to supply their own toilets, sinks and so on.

In addition, hot water is cut off in all Moscow apartments for four to five weeks every summer. The Soviet housing authorities say they do this in order to clean the pipes.

The complexes set aside for foreigners in Moscow are usually walled in and almost always come equipped with round-the-clock Soviet security guards.

According to foreigners and Soviets, the guards have recently increased their surveillance of the compounds.